i have a 95 Grand Cherokee, recently started runnin funny(not ha ha funny). i cleaned throtlle body and the IAC valve which was real bad and it helped for while. i took it for a short drive everything ok. I just got back in from garage and its just has an erratic idle up and down about 3-400 rpm drop. I was supposed to go to Indianapolis for the Jeep roads to rock tour but not looking like it now. I changed the fuel filter today it was dirty and I'm kinda thinkin bad gas, I got gas where I never before just a thought. It doesnt do it all the time just idling intermittently.

 

Oh, I checked for vacuum leaks couldnt find any the engine light is on but car part stores cant read it to old..

 

I just hooked up the scanner to the girl and the oxygen sensor is reading way out of wack. should flucatuate but stays right at 3.2 volts running rich. It did bounce a little bit down to .72 volts and then it started to run bad, I think the sensor is telling the computer wrong reading at the wrong times, I'm thinking just put a sensor in it?

 

I was told i had a bad ignition coil on my Jeep 98 GC not to long ago after i replaced it, it did seem to fix up and down idle.

 

mine is doing this to at idle but when i move its fine it sounds all grumbly and does the 3-400rpm drop

 

I have a 97 Jeep that goes all haywire. I've replaced a lot of stuff on it and I'm tired of putting money in it. I've done a little research and came up with something a little different. Chrysler had a recall a few years back because of a bunch of catalytic converters that went on Jeeps. My Jeep stalls while I'm driving it, doesnt idle right, has no power to it and shifts all crazy. A clogged up converter will make your Jeep act that way. Thats why sometimes it runs great and sometimes it dont. I'm going to check on that here in the next couple of days but I just wanted to see what other people thought about it. Have you guys checked your cat converters? The ones they recalled and never fixed would break apart inside and clog up real easy. Check that out before you start spending a lot of money on all the sensors and fuel pumps the dealers try to make you spend.

 

I forgot to give an update I replaced the 02 sensor and is all good now. I also was in the process of replacing exhaust also sounds good now put on a Thrush welded muffler..