97 Jeep Cherokee: Rough Idle/Misfire

[johnd]

I will be very interested in how this comes out. My '97 Camaro does exactly the same thing-with one exception-the problem goes away when it warms up. I thought it was the alternator dragging the engine down but that didn't turn out to be the case. No misfires at all and plenty of power, just a rough idle that smoothes out at about 1200 rpm.

 

[johnd]

Short answer, mostly the MAF sensor. I cleaned it and the cold idle is about 100-200 rpm higher and most of the shake is gone. [censored] that took a long time to find!

 

[Chris142]

Stop!!!! Don't take anything apart yet. Is this a 4.0l Jeep engine? If so Jeep had a TSB about valvesprings breaking on 97 jeeps.

If it's the 4.0 you have look for broken springs on those 2 cylinders before you rip the whole thing apart.

If it's not a 4.0 carry on.

 

[fonty493]

Only 300 miles into the Auto-Rx treatment and I don't want to shoot myself in the foot by saying I think we've got it figured out but the improvement so far is undeniable. Driveability at all speeds is improved and the idle is starting to get better. I'll keep ypu guys posted.