need help
01-22-2011, 12:59 AM
#1
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Join Date: Jan 2011
Location: texas
Posts: 24
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Year: 1998
Model: Grand Cherokee
Engine: 4.0
need help
98 gc 4.0..... the rpms shoot up n down at low speeds but when I step on it, it runs fine whtcan it be, I need HELP
01-22-2011, 05:01 PM
#5
Member
cel.., check engine light
you dont just want to turn it off. thats not going to help. you need to find out WHY its on. go to your nearest AutoZone or parts store that offers free diagnostics. they can "pull the code" for you. this will give you some indication of what might be wrong. I had the same kinda problem but with some spitting and sputtering and back firing through the throttle body. there are a few different things that might cause this...,
1) coolant temp sensor. (cts)
2) throttle position sensor (tps)
3) crank position sensor (cps)
4) map sensor (?)
5) oxygen sensors (o2) there may be 2 depending on the year of your xj.
this seems to be a common problem.., there a lot of threads with alot of different advice.
could be as simple as a bad connection to one or more of the above mentioned sensors.
could be a vacuum leak.
mine ended up being the front o2 sensor. (about $80). I just unplugged it for now and it runs fine (runs pretty much normal) but still plan on replacing it
soon.
good luck!
could I have possibly missed anything? Anyone?
you dont just want to turn it off. thats not going to help. you need to find out WHY its on. go to your nearest AutoZone or parts store that offers free diagnostics. they can "pull the code" for you. this will give you some indication of what might be wrong. I had the same kinda problem but with some spitting and sputtering and back firing through the throttle body. there are a few different things that might cause this...,
1) coolant temp sensor. (cts)
2) throttle position sensor (tps)
3) crank position sensor (cps)
4) map sensor (?)
5) oxygen sensors (o2) there may be 2 depending on the year of your xj.
this seems to be a common problem.., there a lot of threads with alot of different advice.
could be as simple as a bad connection to one or more of the above mentioned sensors.
could be a vacuum leak.
mine ended up being the front o2 sensor. (about $80). I just unplugged it for now and it runs fine (runs pretty much normal) but still plan on replacing it
soon.
good luck!
could I have possibly missed anything? Anyone?
Last edited by black_police_xj; 01-22-2011 at 05:04 PM.
