1997 Sidekick MAF and/or MAP???????

[3Waggintails]

1997 Suzuki Sidekick JS, 1.6, 5 spd ML 4 dr  97k original miles

By now, FixKick and all else are probably as frustrated as I am with this continued saga. I am utterly at my wits end and so angry and frustrated.

See Posts: Temperature Sensor or Throttle Body
https://www.fixkick.com/bbs2/Suzuki-bbs/...p?tid=2600

and

Throttle Body/TPS
https://www.fixkick.com/bbs2/Suzuki-bbs/...p?tid=2602

So car is still in the shop.  Went in to diagnose and repair a PO400 code that would not die and misfire at idle ( I call it a hiccup but car will statrt and idle at 1500, then 1200 then 1000 then probably about 850 then drop to 500) as well as intermittent hesitation issue when cruising (the 2 threads above out line the dirty details). Drive a few minutes (2-3 miles and no problems except when you stop at light etc.) Idle initiall 850-1000RPM
when you first stop then drops to 500 while you wait for light. Green light, no issue in acceleration.  No hesitation.  Good response. Then when cruising with steady foot on pedal, intermittent hesitation, more foot, gresponds and goes.  Drive little further. repeats.  May do for 2-5 miles driving.  After that, return trip home.  No more hesitation incidents.  Only when stop Idle about 850, drop to 500 RPMS. 

Fast forward to today.

At last posting, the shop had replaced my throttle body with my spare throttle body and TPS (my 1997 car apparently had a 1995 throttle body/TPS out of the factory - who knew??!!)  The one I purchased used was the correct throttle body for my 97 Kick).  Last word was this measure failed.  The car still having the intermittent hesitation issue when cruising at normal operating temperature and idle at a stop would drop to 500!  Same as before when it first went into the hospital.

I went to shop today to talk to mechanic in person and drive car and see for myself.  Questioning the mechanic to see what had been done thus far, before the throttle body and TPS swapped he stated:

1) smoke test -good

2) Vacum test - good

3) confirmed spark plugs removed and gap set correctly

4) timing has supposedly been checked and good

5) Fuel pressure checked - good

6)  TPS calibrated - not just slapped on

7) ISC was cleaned when they cleaned original throttle body, intake manifold, etc. - told it wasnt very dirty at all.
I am told currently no codes and no pending codes.

8) He now states he never thought was TPS and does not think EGR issue anymore.  States he thinks it is MAF and or MAP and if not ECM!!! States he never thought TPS but his boss (owner of shop thought TPS) no test - just symptoms. 

Shocked, I go to drive my car.

Start up from cold (CEL no longer on and based on what he said about drive cycles since THrottle body and TPS swap it would have popped by now- my experience so far ...hmmm ), outside ambient temp about 70 degrees.  Start up and RPMs about 1500, I wait and RPMS drop to about 1200.  Wait more, RPMS about 1100, wait more, RPMS about 1000.  

Out of curiosity, I turn on a/c compressor (no fan) and RPMS drop to 800. Turn of a/c switch back to 1000 RPMS. 

Temperature guage has not moved at all. At the 1000 RPMS, I do not really notice my stutter or misfire as fixkick corrects me.

Pull out to drive car and drive about 1/4 mile.  Temp guage starting to move.  Stop at light to get on interstate, idle is about 800 RPMS. Temp guage now 1/2 way between cold and middle (normal operating temp) of guage for my car. 

No hesitation, good acceleration, etc.  Get on interstate and drive hard.  Want to get to full operating temp and then cruise and check for hesitation. Not sure of mileage/distance but drove at operating temperature about 3 miles and exited interstate.  While waiting at light, RPMS  initially about 800 the suddenly, as usual with my issue, drop to 500 RPMS - can feel engine idle rough. But wait! RPMS bounce up to 1000 for a second then then drop back to 500!!! 

On the way back to the shop with steady (cruising) speed gradually increasing, there comes my hesitation for a brief second. Apply more pedal, car responds and goes. Happens a few times on way back.  If I let off pedal (no pressure a second then re-apply - get hesitation. Push pedal a tad more goes.  It is very suttle. Get back to shop and sit with engine running and RPMS 500. Engine shuddering. Turned it off and went to get mechanic and report.


Start up for mechanic with hood open and he watches and I check RPMS - 500.  He now states that he thinks MAF is intermittently failing.  Said code for MAF popped a couple of times but next check nothing.  Unplugs MAF and 
engine stumbles and shudders and then RPMS start to climb - go to 1000 and pretty much stay there.  He says engine should have died.  I dont know any better and I am really confounded.

He states he now thinks either MAF and or MAP sensor issue and at last ECM!  Really???!!!

I tell him some of Fixkick's suggestions for testing etc and also state we need to kill EGR (golf tee in Fixkick lingo) .
He says no longer thinks EGR issue.  Still does not golf tee vac line to EGR. 

Further discussion and head scratching...he says have you done a timing belt?  I said was done almost a year ago (4/1/19) and car was running great until I started trying to defeat PO400 after 5 years driving no problems.  Foolish me!!!!  Said he was tempted to pull timing cover and check.  If off 1 tooth.....

Wouldnt it have been an issue way before now?  Been driving a year til I stated to try and battle PO400 and then got bad gas (water).

So now what? I am still without car and apparently same problem......

[fixkick]

1997 Suzuki Sidekick JS, 1.6, 5 spd ML 4 dr  97k original miles

By now, FixKick and all else are probably as frustrated as I am with this continued saga. I am utterly at my wits end and so angry and frustrated.

See Posts: Temperature Sensor or Throttle Body
https://www.fixkick.com/bbs2/Suzuki-bbs/...p?tid=2600

and

Throttle Body/TPS
https://www.fixkick.com/bbs2/Suzuki-bbs/...p?tid=2602

So car is still in the shop.  Went in to diagnose and repair a PO400 code that would not die and misfire at idle ( I call it a hiccup but car will statrt and idle at 1500, then 1200 then 1000 then probably about 850 then drop to 500) as well as intermittent hesitation issue when cruising (the 2 threads above out line the dirty details). Drive a few minutes (2-3 miles and no problems except when you stop at light etc.) Idle initiall 850-1000RPM
when you first stop then drops to 500 while you wait for light. Green light, no issue in acceleration.  No hesitation.  Good response. Then when cruising with steady foot on pedal, intermittent hesitation, more foot, gresponds and goes.  Drive little further. repeats.  May do for 2-5 miles driving.  After that, return trip home.  No more hesitation incidents.  Only when stop Idle about 850, drop to 500 RPMS. 

Fast forward to today.

At last posting, the shop had replaced my throttle body with my spare throttle body and TPS (my 1997 car apparently had a 1995 throttle body/TPS out of the factory - who knew??!!)  The one I purchased used was the correct throttle body for my 97 Kick).  Last word was this measure failed.  The car still having the intermittent hesitation issue when cruising at normal operating temperature and idle at a stop would drop to 500!  Same as before when it first went into the hospital.

I went to shop today to talk to mechanic in person and drive car and see for myself.  Questioning the mechanic to see what had been done thus far, before the throttle body and TPS swapped he stated:

1) smoke test -good

2) Vacum test - good

3) confirmed spark plugs removed and gap set correctly

4) timing has supposedly been checked and good

5) Fuel pressure checked - good

6)  TPS calibrated - not just slapped on

7) ISC was cleaned when they cleaned original throttle body, intake manifold, etc. - told it wasnt very dirty at all.
I am told currently no codes and no pending codes.

8) He now states he never thought was TPS and does not think EGR issue anymore.  States he thinks it is MAF and or MAP and if not ECM!!! States he never thought TPS but his boss (owner of shop thought TPS) no test - just symptoms. 

Shocked, I go to drive my car.

Start up from cold (CEL no longer on and based on what he said about drive cycles since THrottle body and TPS swap it would have popped by now- my experience so far ...hmmm ), outside ambient temp about 70 degrees.  Start up and RPMs about 1500, I wait and RPMS drop to about 1200.  Wait more, RPMS about 1100, wait more, RPMS about 1000.  

Out of curiosity, I turn on a/c compressor (no fan) and RPMS drop to 800. Turn of a/c switch back to 1000 RPMS. 

Temperature guage has not moved at all. At the 1000 RPMS, I do not really notice my stutter or misfire as fixkick corrects me.

Pull out to drive car and drive about 1/4 mile.  Temp guage starting to move.  Stop at light to get on interstate, idle is about 800 RPMS. Temp guage now 1/2 way between cold and middle (normal operating temp) of guage for my car. 

No hesitation, good acceleration, etc.  Get on interstate and drive hard.  Want to get to full operating temp and then cruise and check for hesitation. Not sure of mileage/distance but drove at operating temperature about 3 miles and exited interstate.  While waiting at light, RPMS  initially about 800 the suddenly, as usual with my issue, drop to 500 RPMS - can feel engine idle rough. But wait! RPMS bounce up to 1000 for a second then then drop back to 500!!! 

On the way back to the shop with steady (cruising) speed gradually increasing, there comes my hesitation for a brief second. Apply more pedal, car responds and goes. Happens a few times on way back.  If I let off pedal (no pressure a second then re-apply - get hesitation. Push pedal a tad more goes.  It is very suttle. Get back to shop and sit with engine running and RPMS 500. Engine shuddering. Turned it off and went to get mechanic and report.


Start up for mechanic with hood open and he watches and I check RPMS - 500.  He now states that he thinks MAF is intermittently failing.  Said code for MAF popped a couple of times but next check nothing.  Unplugs MAF and 
engine stumbles and shudders and then RPMS start to climb - go to 1000 and pretty much stay there.  He says engine should have died.  I dont know any better and I am really confounded.

He states he now thinks either MAF and or MAP (there is NO MAP sensor only MDP EGR ONLY SENSoR) sensor issue and at last ECM!  Really???!!!
there is no MAP sensor on this car that runs FUELING like the 8valve does, sorry but this MDP only is for EGR testing p0400 .  that is why they call it MDP and not MAP !!!

I tell him some of Fixkick's suggestions for testing etc and also state we need to kill EGR (golf tee in Fixkick lingo) .
He says no longer thinks EGR issue.  Still does not golf tee vac line to EGR.  (if main does not stick open , then then MAIN EGR can NOT CAUSE 500RPM)

Further discussion and head scratching...he says have you done a timing belt?  I said was done almost a year ago (4/1/19) and car was running great until I started trying to defeat PO400 after 5 years driving no problems.  Foolish me!!!!  Said he was tempted to pull timing cover and check.  If off 1 tooth.....
see timing belts done wrong many times, (doing it the wrong way or using wrong marks or setting the tension like fan belt (dead wrong that)like doing it like a fan belt super tight and then later the belt shreds, or jumps tooth cogs ) the book to do this does not LIE)
The EGR defeated TEE test (mine) is only  A TEST< to prove the EGR MAIN DOES NOT stick open, at any time for sure coming to a stop , as it is commanded to close.  for sure.
If sure EGR does not stick then no need to GOLF TEE the hose. sure.



Wouldn't it have been an issue way before now? ( not if INTERMITTENT )!
(sure bad  ISC sure BAD maf both can be intermittent )
think about heat, how heat (thermodynamics) and how when things get hot ,metal expands hot, and ISC jams or for the MAF , fails only hot , (hot means normal hot temps 180f)
The MAF can fail for heat, or vibration or be dead or fully wild and intermittent,

Been driving a year til I started to try and battle PO400 and then got bad gas (water). P0400 is only a detraction, here, forget p0400 , we can fix that way far later, LAST IS BEST.
The problem with P0400s is the CEL glows and the owner ignores it but in fact other key errors area there, set,  P0400 is chicken little cried wolf and every one stopped listening.
You replace MAIN right? (EGR MAIN is BRAND NEW,so if true will not stick nor leak now !)
EGR mAINS that stick cause 400-500 RPM on all car , even done so on purpose in my stall test page EGR..


So now what? I am still without car and apparently same problem...... FIX 500 RPM fix that focus on WHAT YOU KNOW IS WRONG , DIAGNOSE THAT.

Said code for MAF popped a couple of times but next check nothing.  (if this  happens , the maf is bad, or the connector pins to it rusty and green with  corrosion)
The ECU only reports 2 errors for MAF<  dead, stuck high, and dead stuck low. (not weak )


Unpluggling any MAF and (and will cause above to be stored in DTC memory) P0102?
engine stumbles and shudders and then RPM'S start to climb - go to 1000 and pretty much stay there. (yes, called LIMPHOME) and is NORMAL FOR YOUR ACT !
the FSM shows you that and DTC is IN Limphome and the page there tells you the mAF is dead tells you the  ECU EMULATES THE DEAD MAF, and idle controls END, and engine goes rich fuel mix,  and more, read up on LIMPHOME mode,  best it to AVOID that. (it also can melt the CAT if done too long)
The #1 purpose of SENSOR Emulation modes are so car can be driven to a shop not towed..  that is its purpose, only..


He says engine should have died.    (he is just guessing, or thinking this car is some non OBD Car. like VW. from 1979?)
HE IS WRONG, the MAF dead turns the CEL lamp on , and DTC P102 sets and LIMPHOME mode has many bad effects not  just one, and RPM controls go dead, in LIMP.
The maf dead turns on MAF EMULATION mod,  that is a fact, and he does not know that I SEE..
Gee I sure hope that P0102 code was not CAUSED by him pulling its connector, as that Be 100% NORMAL, the code DTC end the emulation effects , all are. and more....
The limphome limits spark timing, idle controls dead, and cause wasted fuel lots.  injections rates are NOW CRUDE in LIMP MODE< for sure.
also the bad effects doing this are less in 96+ then 1995 and older, the new OBD2 is smarter and runs better in LIMP mode,  by OBD2 new DESIGN

if the MAF error pops driving from none to P0102 . (as in not molested,  this error happens, yes, then that  is REAL)

P0102 or P0103 , are MAF  dead codes.. both, stuck low or stuck high there are HARD codes, low codes #  means CATASTROPHIC ERROR Codes means fix me first CODES...

He said maf codes, with no code given, nor how he got it, parked, driving or rapping side of MAF or?....  pulling jacks there..?


Cardone sells, rebuilt MAFs. via car stores.(<this is Ecatalog not a store)               or sold here,   or here searched
$175 approx , top quality them.



P0102.. = bad maf, bad wires to maf, bad pins on maf plug , sure bad ECU, but is  last.  the maf test is 5minutes work at 500rpm,  5 minutes and save $500.... seems no brainer to me..
all it takes is  voltmeter for sure P0102, P0103 set.for sure. Part # 74-10033

if any persons unplug  a sensor and then does not reset the OBD2 DTC codes,  those errors can show up for vast driving cycles.  do not pull sensors , then fail to clear the errors you created, (using a scan tool button clear) or you will spend $1000 on parts not needed, I PROMISE you..

to clear codes one more way, easy is pull the DOME fuse for full minute key off,. and put it back, this clears ECU DTC memory.. all things there DTC )

500 RPM is caused by a  sticking ISC< or ECU is setting other CODES you MISSED,  any time the engine acts funny, (low crazy low 500 rpm happens) scan the ECU..
scan it and ignore, P0400 , we can fix P0400s later, but not now, P0400s is hard work (can be and huge labor,) and best done last.

SCAN the ECU, ok, learn to do that, see what other errors are there and ALL OTHER ERRORS ARE VERY IMPORTANT , not just  ghosts, Important unless playing sensor pull games..
the hard errors, can happen in 1 second flat, like pulling the MAF< ECT , or the like..
learn to scan any time ,  for sure a hot engine,

• ENGINE MISFIRES (P030x codes)
  
• RPMs HOT are wrong. 500 is dead WRONG.. scan it now, at 500RPM failing, and check ISC fully.. clean it. too.
  
• ENGINE power lacks  
  
• ENGINE bogs,  but recovers, fast at WOT right foot..
  
• ENGINE hesitates. but recovers fast..
  
• engine burns too much fuel (gee your O2 front is dead,  , bingo, that's wasted fuel but I do not know 02 (B1S1) is bad for sure, no live data posted driving 40MHP steady
  

once 500 RPM is cured the 02 wakes up and goes closed loop hot idle if not fuel is waste, lots.

Personally I'd test the mAF and find cause of 500RPM that be first. if scanning and driving does not find hidden codes, (means intermittent)
i'd test the ISC even bench tested..
the ISC must open 12vdc applied and close valve, no 12vdc connected,  and not stick or jam.. it is just an air valve, solenoid driven..


Recap:

1. find cause of 500 rpm. (do the tests. I even scope mine and see if the signals to it are correct or dead) Scan the ECU for any errors not P0400...
   
2. forget p0400s, until next week or next year (lol) the valve is closed, be happy it  is..... yes the EGR function is failing, , maybe or not.  don't care now.
   advanced thoughts?here is what ISC signals look like,  on this car..  HIGH volts is open and low is closed, 200 times a second the longer it stays high the faster the IDLE RPM.if this was to be dead,  the ECU  is messed up or is in limphome mode (that is why only scanning the ECU tells you what IT is  doing.) HOT ENGINE, AC OFF..
   

OBD2 ways and means
if a code sets and tells you sensor X is bad.
replace sensor X ( if ECT fails check thermostat first)
and last reset the ECU DTC codes or pull dome fuse.
last drive the car and see of DTC codes return.  DTC means diagnostic trouble codes.. there must be none, P0400, last and the FSM tells you that, too..
FSM = factory service manual.  seen it in sticky post 1 on this BBS page.1..


FYI
P0400 can be hard job and expensive to cure, ( I can for sure tell you how , and in order for easy jobs to  harder and cheaper to more expensive sure CAN)
it has 5+ major technologies at play here,
Electric (ECU commanded VSV) (egr is offline at idle and WOT)
Vacuum ported,  can clog. (clean TB)
Vacuum modulation, (mod valves) not just  one on this car,....
CAT back pressure, to make MOD work at all, no CAT present the  EGR is dead.
Long exhaust path to get EGR flows working  from exhaust port 4 to TB mono port 1.  long hard ugly carbon mess here, (I check this last)
The first test is the stall test on my EGR page..  if this fails, the exhaust path is dead.. carbon packed for sure,the  mono port up top is super easy first cure. check.

[fixkick]

intermittent hesitation issues? 
well gee if engine is at 500 RPM the ECU goes kinda nuts,  500 rpm is not on the fueling map tables (ECU table) (means chart not a sensor) and sure  it hesitates.
how can it NOT? I ASK.?  500RPM is illegal RPM.. 750 is low end. for sure. not 500.....

this is because you (not accusatory means all persons involved) fails to find catastrophic HOT IDLE RPM 500 ERRORS cause, only head scratching and guessing, TPS guessed wrong. ok
500RPM is dead to rights wrong fix this first.
that means find the cause of  that first.. and to diagnose this problem first.. here I will make a list, if car was here, can't do there no idea what the have for TOOLS.
HOT engine,  only.. spark good and for  sure new spark HV wire sets, mag wire is best, and timing right...

1. at 500rpm FAILURE, what does turning the bleed screw do,  CCW (counter clockways) 1 or 2 turns, (gawd I hope you didnt screw it in 8 turns clock wise did you, IDK)?
   
2. TPS  idle switch pin at 0vdc, if not but is 5v that is wrong, fix wrong now, ask. (calibrated wrong , or TV jammed or TV cable not a 10mm spec slack per FSM cable too tight!!!!!
   
3. ISC dead, is it? if you remove the ISC plug (has locks do not force any connector on car, learn to unlock them first) does engine stall or go to 400 rpm
   
4. on normal car 800 RPM normal idle pulling he iSC plug gets you about 400 RPM  see my DRIFT? ISC dead is 400 RPM or even 500, or more accurately super low illegal RPM..
   
5. Then I raise the TV lever there to gain 800 RPM if that fails, that means engine is flooding or running super lean.  but I must try this to see that I HAVE control of RPM by hand..
   
6. I then see if engine was misfiring at 500 stops doing that by holding by hand  the TV lever (cables end)  see if misfire ends at 800 RPM as it must,  yes/no.
   
7. Then I clean the ISC, and test it , i bench test it with 12vdc if that fails it is NO GOOD replace it.
   
8. OK ISC is good not bad, not dead not  sticking, I test the signals from ECU to ISC< to make sure they are correct.
   
9. if The ISC is ok and the ECU + ISC can not get idle to 800 as commanded then the injectors are messed up, but gee bad fuel does that. (fuel pressure is good you said so...)
   
10. bad fuel for sure rust for sure water but omg both are hell on injectors I told you they have 10 micro sized screens inside, that do not want to just go clean by them selves, in fact the injector show uses ULTRA sound and back flushing to get them clean there is no other way besides new or rebuilts  x4 injectors..  try to know that that junk landing on any 1 injector pintle valve tip makes it leak and if it leaks RPM can go to 500. even one cylinder dead or flooding will do that. 
    
11. Again this process is to prove ISC not bad, and is really engine gross misfiring firing (that I can not hear)  if it misfiring hard, step5 then injectors may be bad.
    
12. Bet the car does not hold closed loop at idle..  if it does not that too is first order failure and even causing misfire..
    

the injectors on this car x4 are invisible. the tests are limited to leak down testing on car or off.
the on car test is in the FSM,  using key off pressure drops with injector unplugged or added 1 by 1.  to find the offending injector but see this .next..
left is normal, next to are lean burn, and last is flooding . key off and it leaks, for long time,
The on car tests are for EQUALITY, only, if not equal that odd one is bad. if unlucky (happens) all 4 are like 2 and 3 below and read same but are bad and you will not KNOW IT...on car.






no injector made likes dirt, water or rust for gas, none do.  and will love to cog up.
Many times persons do every test there is, and do ignore misfiring, and at the end and vast costs of parts and labor check the injectors last and bingo.


see real Patterns here first , hope owner gets well soon !!!

https://www.witchhunter.com/spraypattern1.php

[fixkick]

this reasons for complexity is simple , it is called command authority.
if the iSC is commanded fully open by ECU (as yours is) and misfire is so bad , rpm only gets to 500 rpm
then the ISC can not flow more air , that is impossible. and all you get is 500 RPM.
That is why we do tests to see if THAT is happening,
misfiring can be tiny to huge, or crazy bad, all that is checked out carefully
for sure my hand force TV tests.
if spark is good and fueling is wrong check injectors. after testing the MAF.

[fixkick]

the on car injector balance test is not easy but here I  show 3 ways,

leaking injector are easy to find, only the flow tests balance on car is hard.
they make a special tool to do that  (pulser box) to see if all 4 are equal. and not one way low.

[fixkick]

all the above is , for 500 RPM...
that backwards AC RPM , is very very odd, never seen or heard that.
my guess, that is a side effect of LIMPHOME mode not seen by me.

[3Waggintails]

Okay well todays's update:

I called shop yesterday morning and told them I wanted to pick up the car. Its just going to sit there until the MAF comes which is estimated Friday or Saturday. Car driveable and they werent going to touch it anymore til I bring MAF.

Sent driver in my car to pick me up.  Older fellow who has drag racing history etc.  He said I think you need good fuel - not regular gas.  Not saying cure, but better grade - Premium not regular or mid.  Good brand like Chevron.  It should help....(I am thinking you pay bill!  I am on fixed income).  Car has run fine on regular 87 octane since owned.)

He also said car didnt seem to hesitate as long as no go in 5th gear.  BS.  does in all gears - sorry.  I know the car and todays driving was best example yet.

So we go back to shop and I drop him off.  I talked mechanic.  He insists thinks MAF and does not think PO400 gonna rear ugly head.

Keep in mind, he did put the throttle body on that I bought of Ebay.  Is correct for 97. Smaller TPS - bought new. Mikuni brand like original on car.  Calibrated, etc.

So here are my observations:

Drive home and the occassional hesitation but recovers with steady pedal. Can almost make happen by letting off pedal then trying to increase speed. Hesitates then recovers.

Got home and drove .01 miles 3 hours later and returned .01 miles -.02 miles total. Outside temp about 75 degrees. When started car idle up at 1500....wait, wait, wait.  Finally drops to about 1200 rpms then just a hair above 1000rpms. I am looking at temp guage and no movement. Hmmmm not warm enough to move.  I dont know elapsed time but put in gear and drove  to destination.  No problems.  Temp guage coming up slowly - maybe quarter way from cold to middle of guage. Get to destination, put car in neutral and sit.  Watch RPMS.  Idling about 850. Barely the litttle hiccup (misfire) while sitting. Turned off.  

Car off about 10 minutes- if that (walking dogs).  Restart. Rpms go to about 1200 for a few seconds then then drop to about 850.  Car NOT at operating temp.  Maybe now at 1/2 way between C and middle. Get home and put in neutral and sit watch RPMS.  about 850

Same drive this morning and same results as above.  2nd drive was longer and more productive I guess you could say.  Total Mileage about 13 miles with 7 on/off cycles of start drive , stop, turn off.  Do errand. start drive short distance, etc.

Ist destination about 3.5 miles away.  Car at operating temp and when you first stop at stop light, idling at about 850 RPMs. then will drop to 500-600RPMs. Pulling into 1st destination, geared down to second, hesitation and kinda jerky this time. Continue into parking lot slow, hesitaion then go, etc. Hmm. Take care of errand - about 20-25 minutes. Start car and go to next destination  - about .02 miles away.  No problems noted.  Stop at destination, about 15 -20 minutes there - maybe.  Start car and leave for next destination - btw when start car to go RPMS at 850 or so.  Next destination about 1.5 miles away. Same scenario.  About 15 mins or so there.  start up car and go.
Minimal incidents of hesitation all way home.  

Got home and came back out with scanner a few minutes later.  NO CEL (mechanic had cleared I guess cuz not on I got car Tuesday). Reader says 3 codes!!!! Ugh!  Pulled codes : PO102 Mass or volume air flow Circuit low (i think words said), PO400 Generic and first I have ever seen this said "pd" (pending?) PO400 Generic.

Freeze Frame Data:

DTC Frz F: PO102

Fuel System 1:  CL  (OMG closed loop!???)

Fuel System 2: na/a

Load Pct (%): 0.0

(OF) ETC: 178  (What the heck?)

ShrtF1(%): 10.09

Long FT1 (%): 0.0

MAP (in HG) 13.9

RPM min: 777

VSS (mph): 0 (???)

Car sat about 1.5 hours maybe before had to go do next errand.  This would be a longer drive all total about 40 miles but not solid driving. About 50-60% at speeds 50-70 mph.  rest was 25-40 mph.

Started up (about the 13th total on/off key cycle since got car back) and guess what?! CEL !!!! ugh  I knew it was coming. DRive to 1st destination not bad.  Stopped for gas and thought I would humor the driver who had picked me up yesterday and at least try the premium gas.  I only had a qtr tank so.  Filled up premium at Chevron and added the bottle of Chevron Techron fuel injector cleaner you suggested.

Typically at this point, until today, car would not have had many if any hesitations to home.  But not today.  Had many!  Stop at light etc. Start out idle 800-850, then 500 or so. It was awful! Almost like it did not like the premium gas, etc....or so it seemed.  What the heck?

I did not clear codes so could not get any more data when got home.  I tried but all data was same in freeze frame except it said on codes 2 instead of 3 - PO400 generic was 2nd code.  First code was PO102.

At this point keeping car here til Monday.  Can I try to golf tee the EGR just to check? I have no golf tee so can use a screw?   I cannot say with certainty that it has been checked.  Only installed.  Sorry but I am doubting most all mechanics these days.

All my tools are limited as is my knowledge but am okay with trying this and any other simple thing you think might help before return it to mechanic on Monday.  

The more data I can give maybe they can FINALLY figure the crap out.

I still want backpressure test, too.  If nothing else to have at least tried/checked.

Also been reading all stuff on FixKick and saw what you said about hoses on modulator , etc.  God I hope connected right!  I can take pics of whatever you think might be helpful.

BTW when car was idling at 800-850, I switched a/c comp on just to see if RPMS went up.  Nope stayed same  or maybe slight drop.  Did not turn on blower. Was just curious.  In old days, not this car, but old 70's carb cars I thought they used to set idle one with a/c off and with on...dunno.  I probably misunderstood.

One other observation....I just replaced muffler early December around the 1st or so.  Had kept noticing alot of moisture dripping out rear and and first few weeks after replacing when you parked car and it was cooling down would hear "popping" coming from it like metal expansion....never had that happen before with a muffler.  But now I hear rattling coming from it...just noticed.  like already rusted out inside? No visible hole and not loud like a hole but rusting along edges of seams in diff spots. OMG    Walker brand that I got at O'Reilly.  Same as one I had put on before.

[3Waggintails]

3/19/20 Update:

Issue seems to be getting worse.  As long as engine cold/cool drives  and idles okay once at operating temp, then starts the drop to 500 RPM when sitting at idle.  Once hesitation starts, it has become worse, lasts longer, harder to recover and happens more frequently.

Talked to mechanic today and gave stats then I cleared codes and have driven my usual route(s).

Code popped quick this time maybe 2 drive cycles. CEL and codes were:

PO400/pd PO400

Freeze Frame Data

Fuels System 1: OL-Drive


Load_Pct (%): 7.1

ETC (deg F): 180

Short FT1 (0%): 0.0

Long FT1 (%): 1.6

Map (in HG): 5.3

RPM (/min): 2941

VSS (mph):45

Very different from yesterdays data.  Actually had closed Loop yesterday.  

MAF  arriving tomorrow.  I think I will attempt install instead of waiting until Monday.  Do I need to disconnect battery first?  Clear any codes or just hook scanner up and clear codes if if nothing showing?