[sbeduckman]

I've searched and searched, but haven't found a thread with symptoms quite like mine. I'd say around 50% of the time I start my Jeep, the idle goes up to around 2k and sits there. If I start driving it, it goes back to 7-800 by the time I'm out of the neighborhood, and stays there. I do have an exhaust leak at the manifold, but it isn't a bad one. I hooked it up to a diagnostic scanner as it was throwing a code (bad cat, assume it's from the exhaust leak). While hooked up to the computer, it idled at 2k for a minute or two, then 1100 for a minute, then settled in at 750. Throttle position showed 16* (too high I think?) at all idle speeds. Another thing...intake air temp showed 150ish with an ambient temp around 102...seemed high as well.

Is the exhaust leak the culprit for all this? I can't find any vacuum leaks, but haven't looked real hard either. Intake manifold maybe? I bought it with the leak and showing the same code and don't think it has become any worse over the last year or so, but the high idle is a new problem, just showing up a month ago. Aside from these issues, it runs great and has been very reliable. Thanks.

[4x4Outcast]

Try resetting the computer. Disconnect the battery terminal, turn the ignition to "start" (for 5 seconds) three times, reconnect battery and try again. This will tell the computer to reset to factory setting again.

If you have a vacuum leak you will get a CEL code. Exhaust leak will tell the computer to run to try to reach the correct settings on the O2 sensors, which will also give a code.

[JPNinPA]

You have a vac leak that closes when hot. It is likely at the head somewhere. This is somewhat common. Do a little searching on th topic. When teh engine is cold, start the engine and spray around each intake to head area with TB cleaner. Slowly do one at a time and listen for a change in the engine rpm. Likely one of the intake bolts are loose.

[private]

I've got a 2.5L as well, when I bought it, it had a MAJOR manifold leak and done exactly as you describe.

You say you have a leak currently, I'd replace the manifold gasket and torque the manifold bolts to factory spec (this can be a pain because it gets tight back around the rear of the motor).