Surging

Tiny
NSUEKOOL
  • MEMBER
  • 2002 JEEP GRAND CHEROKEE
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 88,000 MILES
I have a 2002 Jeep Grd Cherokee, in the past 3 yrs it has had surging problems when at speeds above 45 mph. I've had 3 IAC replaced when engine light comes on. I've also had the tranmission rebuilt, it still surges whether it's in cruise control or not. Also noticed when it's warmed up it surges more often. It will surge 200/300 rpms, then back down to rpm speed. It does it more often when in over drive at 55+ speeds. At wits end on what problem is, I've asked several mechanics, no one knows. Please help !
Tuesday, January 18th, 2011 AT 1:41 AM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,055 POSTS
Does the check engine ligh continue to indicate a bad IAC?
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Tuesday, January 18th, 2011 AT 8:47 PM
Tiny
NSUEKOOL
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Yes, each time that's what came up when the mechanic pugged it into the computer, which is why he replaced it each time. As soon as it was replaced the light went off. Each time the light came on I had different problems with the car besides surging, 1st time very high idle in neutral, 2nd time high idle again and 3rd time very low idle to the point car stalled at stop.
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Wednesday, January 19th, 2011 AT 8:28 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Either he is getting bad IAC's (remanufactured imports) or there is a wiring problem. With the engine running, move the wiring around to see if that makes a change. If it doesn't, he needs to "live check" the IAC's response to what is happening to make sure it is working properly.
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Thursday, January 20th, 2011 AT 4:44 PM
Tiny
NSUEKOOL
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  • 3 POSTS
I read your responces to my mechanic. His reply was he uses a modis computer on my jeep. He has tried moving the wires and has done that live check as well. All checked out OK. He gets his parts from Car Quest, and 1 time he even went to a Crysler dealer and got the IAC.
Looking at my repair receipts, I have them going out in either July or Aug every year. Last repair was Aug of 2010. Could it mean something is getting hot, don't know? But it acts up more in overdrive when engine is warmed up, then on a cold start and driving in overdrive.
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Friday, January 21st, 2011 AT 8:28 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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If he has checked everything, he needs to move to the PCM.
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Friday, January 21st, 2011 AT 8:30 PM

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