Issue with RPMs, no clue what may be causing issue
06-25-2017, 09:21 PM
#1
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Model: Cherokee
Issue with RPMs, no clue what may be causing issue
Ok so i noticed an issue with my RPMs today, note: auto trans. It idles normally at 750 but and times in P it will jump to 1k then back down to 750 and repeats. when i shift from P to R it jumps to 1.2-1.5k rpms then goes back to normal. when shifting from D to N it almost stalls and when going from R to P it almost stalls. now ive already checked for a vacuum leak using gum cutter, none of the vacuum lines or gaskets showed any increase in rpms when i sprayed them with the gum cutter. its a 99 xj sport, anyone have any suggestions on what to check?
06-25-2017, 09:51 PM
#2
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
06-27-2017, 07:56 AM
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Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
It's not the CKP.
Do you have access to an OBD-II scanner? Check what the MAP, TPS, ECT, and IAT values are at cold startup. Chances are one of those sensors are telling the PCM to dump extra fuel. Could even be the O2 sensor...
Do you have access to an OBD-II scanner? Check what the MAP, TPS, ECT, and IAT values are at cold startup. Chances are one of those sensors are telling the PCM to dump extra fuel. Could even be the O2 sensor...