Okay, I have been having this problem for some time now, and I'm hoping it sounds familiar to somebody...
I have a 98 Wrangler 4.0 liter, if I start it from dead cold, it starts and runs fine all the way until I get to my destination, now the issue... if I stop and shut it off for a few minutes (to run into a store or something) when I get back in and start it again, I get an extreme hesitation and serious RPM fluctuation at idle.
If I am sitting at idle, the RPM's fluctuate between 300 and 1000RPM's (at
300 it ALMOST stalls, but then it catches itself and the RPM's jump back up to like 1000, it does this repeatedly)When I put it in gear and go, the engine hesitates, to the point where it seems like it will stall. The only way it will drive is if I floor the gas. After a few minutes the problem works itself out, but until then, it is virtually undriveable.
My first thought was that it was the TPS (so I replaced it), but the problem is still there. Has anybody had a similar problem, and if so what fixed it? I am pretty handy, doing 80% of the work on my Jeep, but with this issue it seems like I could just keep replacing sensors until I'm in the poor house.
I am getting NO "Check Engine" light, so I don't even have that to start diagnosing.
Thanks for any help in advance,
-John