engine prob.

[jeremy rice]

need some suggestions. I have a 4.0 that i recently did some work on and now it seems to surge or miss while driving. Does it mostly when it is could. It also doesn't have an exact spped or RPM when it does it. It actulay does it sometimes when its just idling. I can't get it to throw a code. Have checked all connections that I can think.
Replaced the trans and the intake manifold gaskets as well as clutch and pressure plate and it ran fine before.
Also have replaced the following --- rotor and cap, spark plugs and crank shaft positioning sensor.

Any help before i take it to a shop would be appreciated.
:aagh:

[rockwerks]

need some suggestions. I have a 4.0 that i recently did some work on and now it seems to surge or miss while driving. Does it mostly when it is could. It also doesn't have an exact spped or RPM when it does it. It actulay does it sometimes when its just idling. I can't get it to throw a code. Have checked all connections that I can think.
Replaced the trans and the intake manifold gaskets as well as clutch and pressure plate and it ran fine before.
Also have replaced the following --- rotor and cap, spark plugs and crank shaft positioning sensor.

Any help before i take it to a shop would be appreciated.
:aagh:

That might be your problem, check for a vacuum leak at the intake

[Twister_ems]

Did you check the timing? Sounds like it might be off a little too.

[jeremy rice]

hanes says with the later models that you can't adjust the timing. ????????

[ArizonaXJ]

Timing is not adjutable.
I had some issues with the wife's XJ not too long ago. Dumped $600.00 in parts and spent a LOT of time trying to figure things out.
A couple of things to check:

1. You replaced the intake manifold gasket; by any chance did you give the exhaust manifold a close look? Maybe cracked ever so slightly.
2. O2 sensor.
3. Throttle position sensor.
4. Idle switch actuator.
5. Vacuum leaks?

The final problem discovered (and was probably the root cause to our problems) was the EGR valve and loose hose clamp on a fuel line.

If you end up in need of a GOOD mechanic, PM me and I will set you up with the guy that fixed my wife's.

[howhypno]

I had the same problem years ago on my MJ, after doing everything I knew I took it to a 'certified mechanic' that put a fuel pump in it(after I'd already done that) and it didn't fix the problem. After that I figured what the heck and threw another new crankshaft position sensor at it. Turns out the one I put on was no good either. It fixed the problem and I've never had it happen again.
At the very least check to make sure the sensor is the same depth as the old one. I found that there is a very slight difference on some of the companies that make them and the depth might not pick up as well.
Just a thought.

[Twister_ems]

Timing is not adjutable. I wasnt aware of this. Guess that could make things easier? lol

[jeremy rice]

used a piece of tubing to check intake manifold for leaks and could not hear anything. I hope that rules out an intake leak. ???? anybody???:baby:

[jeremy rice]

noticed today that it doesn't have any problems when it gets around the operating temp.,just under 210 deg., it doesn't seem to have problems.