Pull the trouble codes from the engine computer using the "check engine light" Self-Diagnostic method. This will at least give you a guide as to what may be causing the problem. I'm going to "cut/past" how I do it from another post I answered, and unless Jeep has changed the procedure it should still work. I DO recommend getting a HAYNES repair manual from the local parts store for YOUR model, look in the Emission and Engine Control System chapter and read the procedure in that manual for you. Has lots of info. Anyway, this is how I do it, hope it applies to your model:
I have a 1996 Jeep Cherokee that will do this when I do an on/off sequence using the key, but only if your check engine light is working.
To do this, turn the ignition key ON, OFF, ON, OFF, then finally ON. (On is the position just before that extra click that starts the jeep) The check engine light will blink the number of the first code digit(count the number of flashes), then pause about 2 seconds and blink the number of the second code digit. If you have more than one error code, the light will pause about 3 or 4 seconds, then blink the first and second digits of that code the same way as before. When the computer is finished blinking "codes". It will flash 5 times, pause, then flash 5 more times to tell you that is the end of the sequence. Post back with what you find out, and someone should be able to answer with more info if you need it. GOOD LUCK!
Friday, December 19th, 2008 AT 5:57 PM