SamistineI have 300,000 miles on my 96 tracker. I have rough, maybe misfire under certain conditions. In Park I can get it to be rough between 2300-3000 rpm. If I disconnect the o2 Sensor it runs beautifully. With 02 plugged in I have negative average term fuel trim from 4-8% through different loads. I can comfortably do 75 mph at 23-25 mpg according to scan gauge. I’ve done 27mpg on one trip. Engine compression is 170, 170, 190, 190.
The more concerning thing is feeling a minor buckling sensation when on the highway Performance Timing Key, it goes away if I shift into neutral and coast. It’s not bad but just odd.
Exhaust always smells awful and makes me sick if I smell it too long. I get a few drops of water with black carbon out the back on initial startup, stains my driveway. Also an initial puff of white smoke if I let it sit for more than 7-10 days. I forgot to replace the valve seals when rebuilding the head.
Maintenance done:
- radiator and head shaved, replaced unrepairable valves (15k miles ago)
- New spark plugs and wires
- new rotor cap
- new fuel injectors
- new bosh o2 sensors
- timing belt and crank bolt
- valve timing (15k miles ago)
- checked cat converter, seems dead, however no blockage in the honeycomb and light came through all of it.
- new EGR valve (because why not)
- I do get occasional egr 0400 code, but does seem to work normally according to tests on your page. The passages were cleaned 15k miles ago but code has been occasionally setting since then and before.
- oil Pan gasket (I know not supposed to have one, but I have no codes from that unless I unplug the sensor lol)
- new used transmission, transfer case, front axle, front differential.
At 300,000 miles would replacing the distributor be worthwhile?
DTC's
drive it and log DTC errors and also check pending DTCs, no why can it buck and not set say P0300 or P03xx
the high pan gasket makes the CKP crank sensor sit that much too high, and can fail (or misfire), but only on some brands of sensors , try the SMP brand claimed to be more sensitive.
that stink is just nasty CO, the EGR erases only 1/2 the CO and the cat eats the rest. so stinks, all normal as is water drips from exh, burned fuell makes H2O as by product of combustion)
the 400 has tests P0400A an B, one is stuck open test other is stuck closed 1996 and up, and can be random and the tests are at fast driving then fast and coast.
so at cruise, say 45mph it bucks or misfires or just surges, ? explain more about this, what is felt.
the cat bad is P0421, I bet your scan too is not seeing all DTCs hidding them for sure pendings.
420 is dead cat, and only sets after all SMOG monitors complete, only then can i t set and only if front sensor passes its tests tool for the full monitors clearing out.
many DTCS do not set (failing) until driven 3 times. (each page 1996, chapters on DTC shows this rule for each DTC error.)
this car haves stock exhaust manifold? and with that , #4 tube not cracked making the top 02 sensor there GO nuts and or RANDOM fail.
shields off to see it. and can fail only as the manifold is at a certain temperature as the crack expands from thermal effects. (iron and heat and thermal expansion effects)
here is the monitors, this is failing to complete and until is complete the DTC many be hidden.
![[Image: monitors.jpg]](https://fixkick.com/ECU/Authority/monitors.jpg)
surge or misfire? if not misfire, (no bad spark coil)
causes are fuel pressure wrong , FPR are failing this old now. and fuel pressure is wild, not at linear rising rates from idle to WOT. takes fuel pressure gauge to find it or see fuel drip from FPR vacuum nipple.
or TPS bad, if a TPS is marginal (intermittent) it tells the ECU you are accelerating at steady cruise and will cause surge. (not misfire)
TPS bad too can cause throttle tip-in hesitation, and is lean out caused, TPS is the #1 sensor for enrich mode to accelerate, so goes lean then power catches up (MAF delays) felt as bog or lack of power only for say 3 seconds or less.
I think we need to know when it acts bad exactly and what the right foot is doing and speed. and on flat ground or hills when it happens (it is misfire or surge) surge is fuel mix related, misfire is spark or hugely rich. mix.
and do not ignore OBD2 pending codes. always look , even drive and log data and watch for any sensors acting strange.
good luck on finding this bug.
fix
The more concerning thing is feeling a minor buckling sensation when on the highway Performance Timing Key, it goes away if I shift into neutral and coast. It’s not bad but just odd.
Exhaust always smells awful and makes me sick if I smell it too long. I get a few drops of water with black carbon out the back on initial startup, stains my driveway. Also an initial puff of white smoke if I let it sit for more than 7-10 days. I forgot to replace the valve seals when rebuilding the head.
Maintenance done:
- radiator and head shaved, replaced unrepairable valves (15k miles ago)
- New spark plugs and wires
- new rotor cap
- new fuel injectors
- new bosh o2 sensors
- timing belt and crank bolt
- valve timing (15k miles ago)
- checked cat converter, seems dead, however no blockage in the honeycomb and light came through all of it.
- new EGR valve (because why not)
- I do get occasional egr 0400 code, but does seem to work normally according to tests on your page. The passages were cleaned 15k miles ago but code has been occasionally setting since then and before.
- oil Pan gasket (I know not supposed to have one, but I have no codes from that unless I unplug the sensor lol)
- new used transmission, transfer case, front axle, front differential.
At 300,000 miles would replacing the distributor be worthwhile?
DTC's
drive it and log DTC errors and also check pending DTCs, no why can it buck and not set say P0300 or P03xx
the high pan gasket makes the CKP crank sensor sit that much too high, and can fail (or misfire), but only on some brands of sensors , try the SMP brand claimed to be more sensitive.
that stink is just nasty CO, the EGR erases only 1/2 the CO and the cat eats the rest. so stinks, all normal as is water drips from exh, burned fuell makes H2O as by product of combustion)
the 400 has tests P0400A an B, one is stuck open test other is stuck closed 1996 and up, and can be random and the tests are at fast driving then fast and coast.
so at cruise, say 45mph it bucks or misfires or just surges, ? explain more about this, what is felt.
the cat bad is P0421, I bet your scan too is not seeing all DTCs hidding them for sure pendings.
420 is dead cat, and only sets after all SMOG monitors complete, only then can i t set and only if front sensor passes its tests tool for the full monitors clearing out.
many DTCS do not set (failing) until driven 3 times. (each page 1996, chapters on DTC shows this rule for each DTC error.)
this car haves stock exhaust manifold? and with that , #4 tube not cracked making the top 02 sensor there GO nuts and or RANDOM fail.
shields off to see it. and can fail only as the manifold is at a certain temperature as the crack expands from thermal effects. (iron and heat and thermal expansion effects)
here is the monitors, this is failing to complete and until is complete the DTC many be hidden.
surge or misfire? if not misfire, (no bad spark coil)
causes are fuel pressure wrong , FPR are failing this old now. and fuel pressure is wild, not at linear rising rates from idle to WOT. takes fuel pressure gauge to find it or see fuel drip from FPR vacuum nipple.
or TPS bad, if a TPS is marginal (intermittent) it tells the ECU you are accelerating at steady cruise and will cause surge. (not misfire)
TPS bad too can cause throttle tip-in hesitation, and is lean out caused, TPS is the #1 sensor for enrich mode to accelerate, so goes lean then power catches up (MAF delays) felt as bog or lack of power only for say 3 seconds or less.
I think we need to know when it acts bad exactly and what the right foot is doing and speed. and on flat ground or hills when it happens (it is misfire or surge) surge is fuel mix related, misfire is spark or hugely rich. mix.
and do not ignore OBD2 pending codes. always look , even drive and log data and watch for any sensors acting strange.
good luck on finding this bug.
fix
http://www.fixkick.com