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jenmal 11-07-2011 09:14 PM

High Revvs when first driving and starting
Not sure if the tranny is sticking or what but, I have a 1999 Grand Cherokee 4.7, and I recently had someone replace the radiator, and since then whenever I first start the car and drive, hot or cold, it seems to have a high rev when first going, and then it subsides after a bout a quarter mile, it revs up to 2k rpm and then acts normal, through the rest of the trip,even at stoplights.I checked and topped off the tranny fluid as a little came out when the tranny cooler lines were removed, and there seems to be plenty of coolant and I bled it and there are no bubbles there. Now, we did not originally fill the system at the bleed hole, we put it in the new radiator directly, and then saw that the coolant was not circulating well and the temp was going up (not driven while this was happening), and then started feeding the bleed hole and the temps regulated after coolant steam and pressure was released. The car does not overheat at all, but just high rev initial drive, and also it starts with a high rev as well!

Someone told me it could be wetness in the tranny cooler lines, but I am not so sure, the engine and tranny were fine until this, very well in fact, so I am wondering what could be causing this as I am concerned that the tranny may be under unnecessary stress. There are no codes either when I try and read from the ignition, done is all I get!! I am confused and worried that the guy that took it apart did not reconnect something, but I checked all the lines and everything seems connected! :confused::confused::confused:


01grand 11-07-2011 09:50 PM

Re: High Revvs when first driving and starting
The transmission computer on the V8 will light up a warning if the transmission is overheating. Also, if the fluid is dark colored or burned smelling there is a problem with the tranny.

Also, when the engine is cold the computer will hold the idle higher to warm up the engine.

jenmal 11-07-2011 11:00 PM

Re: High Revvs when first driving and starting
Thanks. All those things are normal for the V8 jeep, but this is not normal, because it happens no matter if the car is hot or cold. This is my 6th V8 GC, and I have never seen this happen, and I know it is not the tranny going out, somethings not getting enough of something.

JeepMe 11-08-2011 07:39 AM

Re: High Revvs when first driving and starting
I would check your idle air controller and also check to see if your TB blade is getting partially stuck open when driving.

Frango100 11-08-2011 01:08 PM

Re: High Revvs when first driving and starting
Remove the idle air control stepper motor and clean the plunjer well, also give the throttle body a good cleaning. This normally helps on idle issues.

hoffmanestates 11-10-2011 10:15 AM

Re: High Revvs when first driving and starting

nrlewellen47 11-11-2011 04:23 PM

Re: High Revvs when first driving and starting
I just had this same issue. I took out the idle air control valve and cleaned it ( i used rubbing alcohol) and cleaned the entire throttle body while I had everything torn apart. It was surging from 1800 to 2200 or so. Once cleaned it idled much more normal.:thumbsup:

JeeperCreeper24 12-15-2011 05:07 PM

Re: High Revvs when first driving and starting
I had the same issue on my 02 WJ with the V.8 4.7 engine. I replaced the Throttle Position Sensor. $33, 2 screws, and 10 minutes later it was purring like a kitten.

This is the link for the 02 WJ. Not sure if you will need a different one or not.

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