Hi Guys,

Looking for some help here with my 1999 Cherokee...

About a week ago, out of nowhere, my Jeep started having some trouble within the first two minutes after it starts up. It'll fire up fine, but either idling or driving down the road, within the first two minutes, power will drop down to nothing (with or without foot on the pedal) and then rev back up, drop out, rev up, etc. It'll do this for about 30 seconds or so, coming close or sometimes stalling unless I'm able to keep gas on it, and then it seems to run fine after it "clears its throat". After it goes through this and starts running normal again, it may sound a little rough and there may be some minor loss in power, but not enough to say for sure.

Looking for suggestions if anyone has ever had this problem. Could it be IAC valve? I wanted to see what anyone thought before I started purchasing parts...

Thanks a lot!

Cheers,
Joe

 

My first thought is a fuel delivery problem.

Diagnose before buying any part.

 

I had kind of the same problem when I got my jeep, it would start up, idle for 30 seconds or so, and want to stall unless I reved it. It was the aic and it took 3 minutes to clean it, no problems sense

 

IAC*

 

If it happens driving down the road, it probably is not the IAC.

If it tends to happen at 2 minutes after starting the vehicle. That has the hallmarks of an oxygen sensor going bad. The vehicle does not use the oxygen sensors until it reaches certain temperatures/times, at which point it switches from certain "preconfigured" sensor values over to those actually being provided by the oxygen sensors.

My guess is that you have one or more oxygen sensors on the way out, and that when the vehicle first starts using them they cause some air/fuel mixture problems (because the computer depends on them, particularly the upstream sensors, to determine correct air/fuel mixture adjustments), but after they get good and hot they start to function a little more normally.

 

Does that year have the vacuum fuel pressure regulator on the rail?? Maybe it's dumping fuel in the vacuum system? Easy to check. Pull the vacuum line off and see if there is gas there. It should be dry.

 

Check for any codes/pending codes. There may be nothing, but it is always good practice to get that out of the way.