95 Grand Cherokee Laredo. Here's the problem: I start the Jeep, drive a short distance and have to stop at a red light and let it idle for a few minutes. The engine starts to skip. The light turns green and I give it gas. The problem gets worse, tachometer goes all over the place and the car goes really slow, shaking, making lots of noise, and struggling to speed up. Normally this goes on for about 2-3 minutes, and then it runs fine. The problem doesn’t always start at a red light. Sometimes it happens shortly after accelerating, or when I slow down to go around a corner and try to speed up again. It seems to happen more frequently when it’s hot outside, but it usually happens at least once, every time I drive the car. However, it does NOT happen on highway miles, like when I drive to the beach 2 hrs away. It only happens in stop-and-go city traffic. It has been going on for 4 months now. I paid the diagnostic fee at a private mechanic and the dealership and no codes come up on the computer. Please help!

Try Cleaning the IAC Motor and the Throttle body. Carbon can build up and cause all kinds of stalling and idle problems.Might want to check the fuel system,fuel filter and pressure also check for Vacum leaks.

I had the IAC Motor and Throttle body cleaned. Also checked other areas you suggested but the problem is still there although its a little better. Do you think I need a new IAC Motor? Is that expensive? Thanks for all of your help. I really appreciate being able to come here for advice since the local mechanic(s) can't seem to find the problem.

This is the exact same problem I am having...with my 95. Have you found a solution for it?

I had the IAC Motor and Throttle body cleaned. Also checked other areas you suggested but the problem is still there although its a little better. Do you think I need a new IAC Motor? Is that expensive? Thanks for all of your help. I really appreciate being able to come here for advice since the local mechanic(s) can't seem to find the problem.


Also can you please tell me where the IAC Motor is located..not really familar with this part.

Oh, sure. I'm always happy to discuss this never-ending problem. It's been going on for 8 months now! In fact, I'm picking the Jeep up from the shop again today. The cleaning of the IAC motor and throttle body didn't help. I don't know where the IAC is because I had my mechanic clean it. This time I had the fuel filter replaced. This is an expensive fix because it involves removing the entire gas tank. The mechanic assures me that he drove it for 15 miles and it's good as new. We'll see...

Oh, sure. I'm always happy to discuss this never-ending problem. It's been going on for 8 months now! In fact, I'm picking the Jeep up from the shop again today. The cleaning of the IAC motor and throttle body didn't help. I don't know where the IAC is because I had my mechanic clean it. This time I had the fuel filter replaced. This is an expensive fix because it involves removing the entire gas tank. The mechanic assures me that he drove it for 15 miles and it's good as new. We'll see...


Thanks alot for the quick reply...I know I've been going on 4 months with mine. let me know..how its running. also did yu mean the fuel pump was replaced today? I replaced the fuel filter..but that didin't help. Thanks again.

Thanks alot for the quick reply...I know I've been going on 4 months with mine. let me know..how its running. also did yu mean the fuel pump was replaced today? I replaced the fuel filter..but that didin't help. Thanks again.

Oh, no...don't tell me that. It was definitely the fuel filter that was replaced today. Not the fuel pump. I guess maybe that will be the next step if it isn't resolved this time. Good luck.

FYI-my jeep is finally fixed. I had the crank position sensor replaced by the dealer. Now it runs perfectly. I think the key is to have it replaced at the Chrysler/Jeep service center because I had the same part replaced twice before at a private mechanic and the problem continued. From now on I'm taking it to Jeep for all service and repairs. Good luck with yours.

badjeep,

I don't think it was the mechanics fault when replacing the CPS before it did not fix the problem. I believe it is the quality of the parts used. Do u happen to know the brand name of the old CPS that was used, BORG WARNER Crank Sensor are known to have problems with them, so if the mechanic used a BORG WARNER Crank Sensor then the sensor was most likely bad 'Out Of the Box'. I think it is a good idea for everyone to go to the dealership for their parts, unfortunately the dealership prices are outrageous and not all of us can afford it.

Thank You..Thank You..Thank You..Thank You..!!!!!!!
After 4 months with this problem..reading your post. I went and told my mechanic about it. He replaced the part with a dealership part...and it works great! He's been working on Chrysler products for 25 years and never came across this problem. He's putting it in the books. Thanks again.

R Brown,

What exactly was the fix (CPS?)? - For future reference.

R Brown,

What exactly was the fix (CPS?)? - For future reference.

The mechanic apparently used an offbrand crank position sensor. It still had the shaking and popping for 6 minutes..then would run fine. I told him about your post..of some of the off brand sensors being faulty. He replaced it with a dealer part..and it works perfect! I can't thank you enough for this info..it was driving me nuts for 4 months..and nobody knew what the problem was. I was replacing things left and right not knowing what the problem was.