Weird missing problem 4.0L

[JeepSA]

Hi

I have a 98 4.0L XJ. After a recent long trip I started to get a missing problem. The motor would start to idle rough loose its revs. and then starve. The problem was intermittent but got worse to the point wher you couldnt drive the car.
I took it to JEEP to be fixed. So far I have replaced both O2 sensors, the crank sensor, the altitude/octane sensor on the throttle body and the absolute temperature sensor.
The problem is better, but now when running the car under acceleration it seems jump to neutral and gear down. When on a level road and not accelerating everything seems fine?
When I start her cold she also revs very high(2000) for a couple of minutes and then settles down. The first pull off of the day also leads to a starving scenario where the motor wants to die and idles erratically, then she settles in again?

Any suggestions would be greatly appreciated, could this relate to the TPS(Throttle Position Sensor)

Regards JeepSA

 

[Sparky-Watts]

Could be, but also sounds a bit like a plugged fuel filter. Have you changed that? My YJ acted pretty much the same way about a year ago (except I don't recall if it idled up high on start-up), so I changed the fuel filter and it all went away. I always start with the cheap easy stuff first. I guess that's because I'm an optimist and think it's gonna be something cheap and easy....either that,or I'm just cheap and easy...........

 

[Sparky-Watts]

Also, have you checked the MAP sensor? Or do you have one? Or is that what the altitude/octane sensor is? My wife's Camry acted funny like that, and the fuel filter didn't help, but the new MAP sensor did.

 

[mujaman]

try replacing the TPS sensor. no guarantees that will work, but its worth a shot and its one of the first things i would have done. you can pick one up at NAPA for about $60 and put it in by yourself in less than 30 minutes. its a simple bolt-on piece on the side of the throttle body...

 

[dropseys]

My XJ started with problems like that and it ended up being a bad fuel pump. I also read on here where someone else had a similar problem and it was the computer.