Hey everyone, Firstly I have an 05 Tj 4.0, 6 speed manual.
Okay, long story slightly shorter...
About 2 months ago, I invested in a set of autolite xp985 iridium spark plugs, a blue streak coil rail and a set of 12 hole injectors from k suspension.
The jeep prior to the install of parts was running pretty normally but it had a slight flat spot I was trying to eliminate and a smooth idle never hurts.
After the the install of parts I reset the PCM (positive to ground trick, lights on and off) and started it up. The Jeep straight off the bat started to idle at 2000rpms and would climb to 2500 before going down to 1500. The hole tine it kept fluctuating. Just to be sure I did it right the first time, I reset the PCM again bit no difference.
Took it for a drive trying to get some time in, no difference.
Thinking it was possibly the injectors, I put the old factory ones in, no difference.
I did some research and people suggested the exhaust manifold gasket was causing a vacuum leak. I had a felpro one handy so I replaced that. Since I had the cats off, I changed the rms and oil pan gasket as they were leaking.
When I put it all back together, I used the 12 hole injectors and gave the intake manifold a thorough clean and checked for cracks.
Started it up and the idle is lower but sits at 1100rpms consistently now. It's also no longer fluctuating and not showing any cels.
I then changed back to the old standard ntk sparks and factory coil rail, no difference.
I read somewhere that you could cover the throttle body and attempt to suffocate the motor. If it continued to run, you have a vacuum leak, if it stalled, then it was likely an electrical/sensor issue.
I covered the throttle with a cap and the revs dripped to 800 and was idling pretty smooth. I started to take off the vacuum lines all over the intake to check for leaks. Everyone that came off would raise the revs.
Right now I'm at a loss, I have no idea what more I can do. I'm 95% it's vacuum related as I couldn't snuff the motor. Is there anywhere else I could check?
I've got a 3 day high country trek this Sunday and need to solve this issue asap!
Thanks all
Okay, long story slightly shorter...
About 2 months ago, I invested in a set of autolite xp985 iridium spark plugs, a blue streak coil rail and a set of 12 hole injectors from k suspension.
The jeep prior to the install of parts was running pretty normally but it had a slight flat spot I was trying to eliminate and a smooth idle never hurts.
After the the install of parts I reset the PCM (positive to ground trick, lights on and off) and started it up. The Jeep straight off the bat started to idle at 2000rpms and would climb to 2500 before going down to 1500. The hole tine it kept fluctuating. Just to be sure I did it right the first time, I reset the PCM again bit no difference.
Took it for a drive trying to get some time in, no difference.
Thinking it was possibly the injectors, I put the old factory ones in, no difference.
I did some research and people suggested the exhaust manifold gasket was causing a vacuum leak. I had a felpro one handy so I replaced that. Since I had the cats off, I changed the rms and oil pan gasket as they were leaking.
When I put it all back together, I used the 12 hole injectors and gave the intake manifold a thorough clean and checked for cracks.
Started it up and the idle is lower but sits at 1100rpms consistently now. It's also no longer fluctuating and not showing any cels.
I then changed back to the old standard ntk sparks and factory coil rail, no difference.
I read somewhere that you could cover the throttle body and attempt to suffocate the motor. If it continued to run, you have a vacuum leak, if it stalled, then it was likely an electrical/sensor issue.
I covered the throttle with a cap and the revs dripped to 800 and was idling pretty smooth. I started to take off the vacuum lines all over the intake to check for leaks. Everyone that came off would raise the revs.
Right now I'm at a loss, I have no idea what more I can do. I'm 95% it's vacuum related as I couldn't snuff the motor. Is there anywhere else I could check?
I've got a 3 day high country trek this Sunday and need to solve this issue asap!
Thanks all
