Low RPM / Stuttering - Inconsistent

[sina27]

Hello - 

Got a 96 Tracker 2WD 5 speed. 

I've noticed lately that after I start the car cold, the idle is well above 1000 RPM (as it should be when cold), and then when almost fully warm the idle drops down to ~800 RPM (where it should be?). 
The car drives fine when warm and the idle usually stays around 800 RPM - but sometimes when I come to a full stop and throw the car in neutral, the idle drops  VERY low and the engine stutters (but doesnt die). When this happens, the engine usually brings the idle back up to 800 RPM. 
Its only when I'm accelerating, and then stopping / throwing the car in neutral the RPM dips very low, and stays low for about 10-15 seconds before it starts coming back up. 

This problem isn't very consistent, I sense that when I've been driving the car for a while (at least 15-20 minutes and its very warmed up) the idling problem goes away. 

Any thoughts on what can be causing this? Would it have to do with anything related to the air intake? Maybe some time of air sensor, air leak, or dirty air filter? 

Thanks

[fixkick]

Hello - 

Got a 96 Tracker 2WD 5 speed. 

I've noticed lately that after I start the car cold, the idle is well above 1000 RPM (as it should be when cold), and then when almost fully warm the idle drops down to ~800 RPM (where it should be?). 
The car drives fine when warm and the idle usually stays around 800 RPM - but sometimes when I come to a full stop and throw the car in neutral, the idle drops  VERY low and the engine stutters (but doesnt die). When this happens, the engine usually brings the idle back up to 800 RPM. 
Its only when I'm accelerating, and then stopping / throwing the car in neutral the RPM dips very low, and stays low for about 10-15 seconds before it starts coming back up. 

This problem isn't very consistent, I sense that when I've been driving the car for a while (at least 15-20 minutes and its very warmed up) the idling problem goes away. 

Any thoughts on what can be causing this? Would it have to do with anything related to the air intake? Maybe some time of air sensor, air leak, or dirty air filter? 

Thanks

all normal hot is 750 to 850 RPm spec.
cold varies by out door temp and for sure how cold the coolant is, at 150F the cold temps end and hot 800 arrives.
the lower RPM is the EGR main sticking open
as you come to a stop or just cut throttle to zero, (right foot) the EGR is command close, if it dont close rpm can go to 400RPM and engine misfires and shakes hard.
a very common thing, this,  EGR might be cleaned (main) to cure this, 50% change of success. if EGR is super old , chances less.

Im pretty sure this is it,  and not something far worse.  injectors leaking or crank pulley front falling off. is it loves to do latter.
good luck to  you !!!!

[jwunsch]

all normal hot is 750 to 850 RPm spec.
cold varies by out door temp and for sure how cold the coolant is, at 150F the cold temps end and hot 800 arrives.
the lower RPM is the EGR main sticking open
as you come to a stop or just cut throttle to zero, (right foot) the EGR is command close, if it dont close rpm can go to 400RPM and engine misfires and shakes hard.
a very common thing, this,  EGR might be cleaned (main) to cure this, 50% change of success. if EGR is super old , chances less.

Im pretty sure this is it,  and not something far worse.  injectors leaking or crank pulley front falling off. is it loves to do latter.
good luck to  you !!!!

This problem isn't very consistent, I sense that when I've been driving the car for a while (at least 15-20 minutes and its very warmed up) the idling problem goes away.

^ I had the same, my problem's inconsistency was very much linked to outside temp and what speeds I was driving. Fine at 10C, not fine +5C - 0C or below 0C (Fine at 50F, not fine 41F - 32F or below).


I suggest getting IR gun to check the STAT housing to verify temps after driving say at least half a hour. I had similar issues with -91 Vitara G16a (Sidekick in US?).  My posts (1991 Vitara G16A frigid) but probably not worth reading all that b$.

My old STAT was open at all temps, fan clutch was semi sticking etc.

I replaced STAT, fan clutch and they helped a lot, but here at winter the car still over cools, so I blocked RAD with cardboard as I some times got CEL 13 due to to low temp and O2 sensor test failing.

After adding block for RAD those stuttering issues ended. (RPM going so low even RPM meter shows 0, but engine still manages to bounce back to idle). Anyways It's easiest to check the water temps before you go deeper into EGR and other stuff you need to dismantle.

As far as I can guess, if the temp too low ECU has problems guessing if it should use "choke" or not. And when you constantly linger on the borderline it causes problems (and high fuel consumption).

ps. Additional benefit, I can get the cabin hot now

[fixkick]

all normal hot is 750 to 850 RPm spec.
cold varies by out door temp and for sure how cold the coolant is, at 150F the cold temps end and hot 800 arrives.
the lower RPM is the EGR main sticking open
as you come to a stop or just cut throttle to zero, (right foot) the EGR is command close, if it dont close rpm can go to 400RPM and engine misfires and shakes hard.
a very common thing, this,  EGR might be cleaned (main) to cure this, 50% change of success. if EGR is super old , chances less.

Im pretty sure this is it,  and not something far worse.  injectors leaking or crank pulley front falling off. is it loves to do latter.
good luck to  you !!!!

This problem isn't very consistent, I sense that when I've been driving the car for a while (at least 15-20 minutes and its very warmed up) the idling problem goes away.

^ I had the same, my problem's inconsistency was very much linked to outside temp and what speeds I was driving. Fine at 10C, not fine +5C - 0C or below 0C (Fine at 50F, not fine 41F - 32F or below).


I suggest getting IR gun to check the STAT housing to verify temps after driving say at least half a hour. I had similar issues with -91 Vitara G16a (Sidekick in US?).  My posts (1991 Vitara G16A frigid) but probably not worth reading all that b$.

My old STAT was open at all temps, fan clutch was semi sticking etc.

I replaced STAT, fan clutch and they helped a lot, but here at winter the car still over cools, so I blocked RAD with cardboard as I some times got CEL 13 due to to low temp and O2 sensor test failing.

After adding block for RAD those stuttering issues ended. (RPM going so low even RPM meter shows 0, but engine still manages to bounce back to idle). Anyways It's easiest to check the water temps before you go deeper into EGR and other stuff you need to dismantle.

As far as I can guess, if the temp too low ECU has problems guessing if it should use "choke" or not. And when you constantly linger on the borderline it causes problems (and high fuel consumption).

ps. Additional benefit, I can get the cabin hot now

that is correct, but the OP never told that outdoor temps were at (record in Sweden 1942 −20.6 °F) −29.2 °C in Orland.. ( not something easy do work with)
nor if the gauge for temp drops.
the EGR line G16 loves to stick. when old.. (and for sure hot when metals in it expand and are not equal (steel and aluminum( my 96 cleaned it like 4 times, and was good for say a month that fails again)
the EGR main has  a valve inside, that has shaft and the shaft packs in carbon and sticks, some can be cleaned but can be 1/2 effective,
he can also scan this Cars PCM using OBD2, if USA car,, and see if the thermostat never loses control once it is how, all USA cars, 1996 or newer we can do that, very easy, if no logger for tool , then 2 persons do that safely..
his car is Tracker and is not sold in EU, and only in Canada or Alaska would this get that cold here, in N.America's
The Trackers here were made in CAMI Canada plant. I owned 4wd version of his 96 here. I have scan data on it, too.. logs.
the 96 Trackers in USA, the P0117 /0118 will set if the thermostat goes nuts. here.. (only scanning for DTCs will find it and scanning for sure when RPM fails, too, is a win)
The 96 has clock timer inside that if it takes too long for the thermostat to go correct is sets the above code DTC, 150f is the threshold.. cold to hot.. in our cars.. (USA) remember OBD2 is a USA invention, and law here 1996 plus, no copied world wide.
The make the car under other names in canada too, Sun Runner is one, and more. So in truth Have no idea at all where OP lives nor in what country bought new.... Klondike to key-west FL, is huge. area.

[fixkick]

one simple way to prove the EGR Main is not the problem , really super simple.
pull the vacuum like the EGR MAIN , it's on the rear #4 intake tunnel,  
put a golf Tee in the hose you removed, at end.
then flex the EGR test ring in Valve feel it open and close, and NOT STICK, it goes thunk sound as it closes. if sticks, end story.(solved)
if not sticking (hey some only stick hot,don't burn fingers)

drive, if car does not go low RPM crazy now, BINGO,  a super simple and easy test.. no OBD2 scan too needed..

see my photo here on EGR gen 3 page  The bark tube is the exhaust pulse output the the modulator, I am not talking this hose, large but the tiny vacuum hose not seen below.
see this ring, (can only be felt or seen with a mirror on G16B 16valve engine, as he has. flex that ring, say 5 times,  for sure learned on new valve the feel of it.






my uSA only Gen 3 EGR page is here, covers the whole mess, (a vacuum Rube Goldberg mess) 1996 is Gen 3 USA EGR level III (EPA madness)



here is my Thermostat going nuts on 1996 (its takes 10 times the distance to hit 180F.. the President of the STANT company shows a great video of why thermostat only last 7 years.

the Thermostat  can be stuck open or closed dead.
or does this nasty trick , seen here 1996 my tracker.  The SLUG-O-STAT slow as slug. then when hot, it was too LOW 160F and is FAIL #2 ! so this stat is DOUBLE BAD.. slow and wrong..
that wax pellet inside does not last forever, not one does. note the working MAF !

and you will never resolve (human eyes ) dash gauge a loss of 20F temp, there are no temp number son the gauge, its just COLD >>>>>>>HOT, and that is it, so using scan tool WINS.

[fixkick]

Hello - 

Got a 96 Tracker 2WD 5 speed. 

I've noticed lately that after I start the car cold, the idle is well above 1000 RPM (as it should be when cold), and then when almost fully warm the idle drops down to ~800 RPM (where it should be?). 
The car drives fine when warm and the idle usually stays around 800 RPM - but sometimes when I come to a full stop and throw the car in neutral, the idle drops  VERY low and the engine stutters (but doesnt die). When this happens, the engine usually brings the idle back up to 800 RPM. 
Its only when I'm accelerating, and then stopping / throwing the car in neutral the RPM dips very low, and stays low for about 10-15 seconds before it starts coming back up. 

This problem isn't very consistent, I sense that when I've been driving the car for a while (at least 15-20 minutes and its very warmed up) the idling problem goes away. 

Any thoughts on what can be causing this? Would it have to do with anything related to the air intake? Maybe some time of air sensor, air leak, or dirty air filter? 

Thanks

are you in USA or Canada and if in USA is it hot or cold there. (Montana and key west,  are not the same) this time of year.  see my simple EGR test below.

[sina27]

Thanks for the repy - 

I'm in California, and it has been a bit cold lately (45F evenings).

I removed the EGR valve, and I noticed that the bolts securing it in weren't very tight. In addition, the gasket completely deteriorated upon removal.
I cleaned the intake and outake parts of EGR valve using some carb cleaner. The valve snaps back well, and I re-installed with a new gasket. So I don't think it is sticking. 



The problem didn't really go away. I feel like when the car is still cold, it still dips down to low RPM when I quickly go into neutral and take my foot of the gas. But once it is warmed up, it is fine. 
I've also noticed that when I'm driving (after I've been driving for 30 minutes), that the temperature is a bit on the low side - If it is cold out (~45F), and my heater is running, sometimes the temp needle is below the halfway point on the gauge ( I would say the needle is 30-40% of the gauge, 50% being the midway point).
Is this a problem? should it not be running this cold? 
I replaced the radiator and thermostat about 6 months ago. I noticed that the new thermostat I got (from NAPA) had a different looking gasket than my old one (the old one looked more like a fitted O-ring, whereas the new one was a gasket that sat above the stat and came into contact with the stat housing). 
Maybe my thermostat is garbage? 

I will try your EGR valve test while the car is running, basically I will push in the valve and if it stalls, its all good? 

You mentioned using an OBD2 reader. I have one. However, my check engine light isn't on. Is it worth scanning the car with my OBD2 reader even though the check engine light isnt on? If so, what should I scan for? The scanner I have isn't the nicest one, its a Bosch OBD1000:
https://www.boschdiagnostics.com/diy/pro...h-obd-1000


Thanks
Sina

[sina27]

I might probably buy a new stat to be on the safe side - 

what is your go to stat for a 96 tracker, which comes with the seal / gasket? There are alternate temps, but the one I should go with is 180F, correct?

[fixkick]

i ran the 195f in mine,  180f is stock. rockauto and all stores sell it. (warning some makers of silly thermostats make you buy the rubber right one, as  separate boxed part !!!!!!!
Stant brand is my fav. but there are lots of others just as good.
Low RPM cold how low, below 800?  THAT IS NOT THE egr THE egr iS 100% off line cold,  ECU rules.
make sure the front crank shaft 17mm pulley bolt is at 94Ft/lbs torque or the crank snout key shears. and worse. this is the day 1 check of all G16, hand on wrench checked, (clock wise is tight, here) RHT

Ok now we have better facts far better. (evidence all , helps,) good and bad, all helps.

45f is not cold, its actually warm, for engines. -25f cold. or 0f.

PRIME EVIDENCE #1 here.!
the heater is telling you the thermostat is no good.  (when you turn on the fan , in worse case, (not recirc mode) cold 45f air hits the core. (heater)
and cools the water the thermostate 100 % sure, corrects that effect, in short seconds. (near instant) if not the themostat is bad.
the 1996 all have the rubber ring thermostat, every one does.  and 4mm lip edge in the intake matching that newer manifold.
that must be there or the thermostat floats and goes nuts, (no paper gaskets allowed, see?)

see my frigid kick page. the TSB is there and covers all that back to 1992, forward, by VIN.
96 all have the 4mm stat.
the rubber is like 5mm compressed to 4mm and seals.
there you go you bought the wrong thermostat,

he is mine, done right