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Jeep 2001

I have a 2001 Jeep Grand Ch. Limited, 4x4 all wheel, 4.7 V8, 75,300 miles. It has spent more time in the shop then in my garage the past 2 years. I do have one major issue that no one can seem to resolve. I have had it into Aamco, Edward?s transmission and a local auto mechanic.

When slowing down it shifts into 2nd (I am guessing on the gear) very hard. It has even chirped the tires in the garage when shifting into reverse. This happens very intermittently, about once every 2 weeks. Each time I have had it into a mechanic they cannot get it to act up, naturally! When a diagnostic is ran on it all that shows is a vacuum leak related to the gas cap and an O2 sensor issue (both have been fixed). After fixing these two issues my engine light shut off. Its been about 3 weeks and my engine light has returned and my cruise control is no longer working. I am about at my wits end. Any suggestions?

Here is a list of items that have been fixed in the past 9 months:

A/C module/relay ( was not blowing air out)

new tires

new brakes

new rotors

new back brakes (the new ones were extremely loud)

4 new O2 sensors

Current issues:

cruise control light comes on but cannot set it

still down shifts extremely hard

shifts into drive and reverse hard and rocks the vehicle

back brakes have started to become loud again

Thank you

does the jeep seem to idle high? A lot of times if the vehicle is idling too high it will shift into drive and reverse harshly.
The local auto parts store should be able to get the engine light codes for you for free and even give you a print out of what the code is and what it means.
come back and post what the codes are and the definition of those codes and we can probably narrow down your problem. due to the fact that the cruise control also isn’t working, I’m betting there is a problem with the throttle position sensor. The vehicle will still run without a signal from the TPS but cruise control will not work. You may also notice things like harsh shifting and higher than normal idle.

As far as the brake noise goes, it depends on what type of brake pad you had put on. I have a 2000 grand cherokee that I just replaced the rear brakes on. I bought a brand that a local parts store sells called “thermo-quiet”. I have had great service out of those pads on every vehicle I own. I have even installed them on customers cars. they aren’t the cheapest pads, but they are good quality. I think the rear pads set me back around 50 bucks

Thank you very much for your suggestions.

I am not sure what it should idle at, it stays around 2000rpms and at higher speeds it will sometimes jump upand down from just under 2500 rpms to about 3100 rpms, in a rhythmic type pattern. Now it does idle high when I first start it and sometimes it does not stop until I put it into reverse.

I will get back to you after I find out the codes. Are the eng light codes diff from the diagnostics that were ran and showed just the O2 sensors?

Thanks again

That’s way too high. It should idle somewhere between 500-1000 rpm. This probably is the reason for the harsh downshift-- the engine’s generating a lot of power when it’s supposed to be generating very little or actually slowing the vehicle. The trouble could be a bad idle controller or a big vacuum leak-- I don’t really see why the mechanics have had such a hard time figuring it out!