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ipath68 06-17-2012 10:11 AM

Weird Idle at Start up
Ok so lately on colder mornings my Jeep (2004 Rubi) will start and then the idle will go to about 1300rpms, then down to about 900rpm stumble for a couple of seconds go back up stumble til I give it some gas shoot the rpms up and then it back to normal. Checked for possible vaccum leaks couldn't find any, cleaned the throttle body good. Replaced the IAC valve because the other seemed questionable. Is there something else I should be looking for? any suggestions would be great. I'v searched and seen people say TPS but I haven't seen anybody say that it worked or not?

ipath68 06-17-2012 01:01 PM

I forgot to mention no codes...

ipath68 06-17-2012 03:23 PM

Anyone.....? Don't want to keep throwing parts at it and hope they work.

Molaker 06-17-2012 06:04 PM

The TPS in a 2004 (2003 +) is different than the earlier models and is not nearly so prone to failure as the old wiper arm type. If you have a decent digital volt meter, you can test it.

When you replaced the IAC, did you remove the small mounting block it fits into and clean it as well? The IAC plunger seats in it and if there is enough crud build-up, it could feasible cause this.

A couple more possibilities are the MAP (manifold absolute pressure) and the MAT (manifold air temp). Of course, that's just throwing parts at it.

Since you say it is only when it is cold, you might try disconnecting the oxygen sensors - one at a time to see if this stops the fluxuations. It may well alter the idle, but look for fixes for the variations you are reporting.

ipath68 06-17-2012 09:57 PM

I cleaned the block also, I'm hoping I get another cool morning when I can check it again. Sucks working out of town.

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