Bucking/stall issue

[Outlawpuppy]

Hi all! I posted a few weeks about about a pretty horrible bucking/misfire issue i was having with my 98. Basically I was getting p1391 error code and had a pretty good hole in my manifold. You guys recommend that I replace my manifold if changing the sensor didn't do anything and putting the old sensors back in as well. Anyways I went and did those things with mixed results. The bucking is now less, but still enough to drive me nuts, it's starts when I hit 2k rpm when under load and stops at like 2.5k rpm there are times when it doesn't even do it at all either but it seems to happen randomly. I appreciate any and all insight, idk what to do now

 

[ItchyDong]

Am I missing something? P1391 is a cam crank correlation code. You need to attack that. It has nothing to do with a hole in a manifold. That’d throw lean codes amongst a million other symptoms.

 

[Outlawpuppy]

Am I missing something? P1391 is a cam crank correlation code. You need to attack that. It has nothing to do with a hole in a manifold. That’d throw lean codes amongst a million other symptoms.

Yeah, maybe im just stupid? I replaced my cam and crank sensors, spark plugs too. I don't really know what the next step is. I don't think it's internal to the engine because it only happens when im in gear. So drive train?? But what would be happening at 2k rpm so reliably? Could the ecu be messed? Thanks again.

 

[Cooper Smith]

Hi all! I posted a few weeks about about a pretty horrible bucking/misfire issue i was having with my 98. Basically I was getting p1391 error code and had a pretty good hole in my manifold. You guys recommend that I replace my manifold if changing the sensor didn't do anything and putting the old sensors back in as well. Anyways I went and did those things with mixed results. The bucking is now less, but still enough to drive me nuts, it's starts when I hit 2k rpm when under load and stops at like 2.5k rpm there are times when it doesn't even do it at all either but it seems to happen randomly. I appreciate any and all insight, idk what to do now

Don't just throw parts at it, sounds like this might be over your head. Are these Mopar sensors? Start wiggling wires, might be an open/short in the harness. A live data scanner will be useful.

https://naxja.org/threads/p1391-stumped.1145299/

This is an XJ forum, but lots of good and relevant info on there. XJ, TJ, LJ, doesn't matter AFAIK. These PCM's are very picky about tolerances with sensors. You need to use Mopar sensors. I had a TPS on a 2.4 fight me, as it was an O'Reilly's part. Many people here fight with non OEM CKP's, CMP's, O2 sensors, etc.

No, this has nothing to do with the drivetrain. This an electronic or even timing chain issue between the PCM, CKP, and CMP.