jimmydaux
NAXJA Forum User
- Location
- Centerville, Utah
Ok guys, Ive been having quite the quandry runnin for the last few months on my XJ.
I have stuttering problems and have searched High and Low for some specific answers but cant seem to find them.
I'll do my best to describe the symptoms so this can hopefully help people out later.
1998 4.0 aw4 np231 192,000 miles
Replaced cracked manifold with APN Header about 2 months ago
Replaced o2 sensor at the same time with a unit from OxygenGeek.com
I never have starting issues.
1. Throttle would stutter and buck when trying to maintain speed.(consistent throttle and onlly in one throttle position) It would happen regardless of engine temperature or operating time. Eventually this threw a CEL saying it was the tps which I suspected. I replaced with a new unit from AutoZone because they had a 2 year warranty.
2. A similar problem started a few weeks later, this one was differant though. It was more erratic. It would stutter over a larger range of throttle positions. It would backfire through the intake. If I were to hold the throttle consistent it would continue to stutter so much that speed would not increase. If you were to floor it, it would jump up and go. If you were to let off the throttle and go right back to where you were before it would seem like it reset and the engine ran perfect.
3. I warranty exchanged the AutoZone TPS. This seemed to fix the problem or at least make it better. After about 2 weeks it started again. The syptoms were just like #2 above. It seems to be more consistent this time. Either that or Ive been able to pinpoint the behavior a little better. From a cold start for the first 5-10 seconds of driving it wont do it. Immediately after that the stuttering will start in the lower throttle positions. It will cycle through about 3 times and then be fine. (cycle being... Stutter, release throttle, reapply throttle, ok for a second, then start stuttering again, repeat) After those cycles run through, it runs like a champ. No issues, no hesitation, no stuttering. If I were to turn the engine off for 30 minutes or so, it would have the same problem, even though the engine temperature is still very warm. Once again, after the stutter cycle completes it runs perfectly.
With how it behaves, Im almost wondering if it is the o2 sensor that has issues. I wouldn't think that the TPS would be off an on so predictably. Its almost like once the o2 sensor heats up from the exhaust or the o2 heater the problem goes away. If it sits for 30 minutes or so, the exhaust may have enough time to cool down and cause the problem again momentarily until it heats back up. The only time its caused problems is when I try and cross traffic or merge and it stutters. I can easily let off and reapply the gas and it jumps back to life.
Do you guys think this problem could be the 02 sensor, or do I try and get a better TPS sensor from napa or the dealer? Or am I overlooking something as a plausible culprit?
Any help would be greatly appreciated.
Thanks guys,,
Jeremy
I have stuttering problems and have searched High and Low for some specific answers but cant seem to find them.
I'll do my best to describe the symptoms so this can hopefully help people out later.
1998 4.0 aw4 np231 192,000 miles
Replaced cracked manifold with APN Header about 2 months ago
Replaced o2 sensor at the same time with a unit from OxygenGeek.com
I never have starting issues.
1. Throttle would stutter and buck when trying to maintain speed.(consistent throttle and onlly in one throttle position) It would happen regardless of engine temperature or operating time. Eventually this threw a CEL saying it was the tps which I suspected. I replaced with a new unit from AutoZone because they had a 2 year warranty.
2. A similar problem started a few weeks later, this one was differant though. It was more erratic. It would stutter over a larger range of throttle positions. It would backfire through the intake. If I were to hold the throttle consistent it would continue to stutter so much that speed would not increase. If you were to floor it, it would jump up and go. If you were to let off the throttle and go right back to where you were before it would seem like it reset and the engine ran perfect.
3. I warranty exchanged the AutoZone TPS. This seemed to fix the problem or at least make it better. After about 2 weeks it started again. The syptoms were just like #2 above. It seems to be more consistent this time. Either that or Ive been able to pinpoint the behavior a little better. From a cold start for the first 5-10 seconds of driving it wont do it. Immediately after that the stuttering will start in the lower throttle positions. It will cycle through about 3 times and then be fine. (cycle being... Stutter, release throttle, reapply throttle, ok for a second, then start stuttering again, repeat) After those cycles run through, it runs like a champ. No issues, no hesitation, no stuttering. If I were to turn the engine off for 30 minutes or so, it would have the same problem, even though the engine temperature is still very warm. Once again, after the stutter cycle completes it runs perfectly.
With how it behaves, Im almost wondering if it is the o2 sensor that has issues. I wouldn't think that the TPS would be off an on so predictably. Its almost like once the o2 sensor heats up from the exhaust or the o2 heater the problem goes away. If it sits for 30 minutes or so, the exhaust may have enough time to cool down and cause the problem again momentarily until it heats back up. The only time its caused problems is when I try and cross traffic or merge and it stutters. I can easily let off and reapply the gas and it jumps back to life.
Do you guys think this problem could be the 02 sensor, or do I try and get a better TPS sensor from napa or the dealer? Or am I overlooking something as a plausible culprit?
Any help would be greatly appreciated.
Thanks guys,,
Jeremy
