For a 1998 Cherokee Sport, 4L, 5spd: Vehicle after startup, hot or cold, randomly misfires, feels like it's not running on all cylinders, popping sound coming from air intake (like carburetor backfire sound, back in the day when we had carbs!). No code generated. Had complete tuneup recently, replaced fuel pump, Crank Position Sensor, symptoms continue. After misfire event, vehicle straightens out and runs fine for rest of operation provided I don't shut it down. Any restart will run the risk of a new misfire episode. I know the misfire's about to happen because engine idle is very unstable, dropping then rising dramatically.

Forum search indicates anything from carbon on valves, to TPS, to injector wire resistance. Any way to narrow this thing down, especially in light of no code being generated?

Any help much appreciated! Thanks!!

 

First off welcome from eastern PA And for ypur question try cleaning your iac and tps that might help the iac controls you rpms at idle when they are dirty sometimes they will act up

 

Thanks for the welcome, interest, and suggestions jd4x426. I'll try to get on that ASAP. Any other thoughts would be appreciated.

 

I got the same problem as you and working on finding out what it is. I cleaned my IAC and it was pretty carbon-ed up. It idled a little better than before but it still does this rough start every now and then. I've been told leaking injectors will leak overnight as it sits and cause this issue.

I recently stuck a can of seafoam in the tank and filled it up half way. I haven't had this rough start all week so far. Too early to tell if it's cured but it's been four days and no issue so it's looking good.

 

you also might want to change your fuel filter