Jaster343

I have 97 XJ 4.0L auto w/ 268,000m original motor and tranny. The truck has run like a top for the three years that I have owned it until about a month ago. I was having trouble with engine temp, I installed a new aux fan and had to wire a new relay since the old system had a gremlin. Problem solved and new one created, since I disconnected the battery to do the electric work I must have reset the computer. Within about 25 drive cycles the acceleration power dropped off a slight bit, then the rough idle began. First it would idle rough in drive at a light or on the approach to a stop sign, eventually it would idle rough in park also. When I say idle rough I mean the RPMs would drop off, snap back up, drop to the verge of stalling and sometimes hover in the 500-600 range. Eventually while accelerating the engine began sputtering. These problems do come and go and sometimes the truck runs great for a day or two. Now the stalling has begun, while making a slow turn or stopping for a light the truck will either stall or the engine will just drop out. I have tried to read as many of the related posts as possible and I have followed some of the advice.

Things I've done:

Checked all electrical connections at the coil, distributor and injectors
Cleaned throttle body
Checked for vacuum leaks
Checked for codes
Reset computer (temporary fix for a few drive cycles)

Any help is appreciated and I'll answer all questions that I can as I'm sure I've left things out.

Radi

Inspect the IAC and clean it if necessary, sounds like it's sticking. Might also check the TPS.

4wheeldrivenewbie

in the renix it was the egr valve for me that was causing rough kinda idle and stalling more so when trying to backup you would press the pedal and it would hesitate and then stall out when u let off

Jaster343

So I pulled the IAC and gave a good cleaning. Reinstalled it, idled okay in the driveway for about 20 minutes but during the road test it started acting up again. The TPS appears to be working fine after checking the ohm's. Is there a chance I have bad O2 sensors or MAP sensor?