So I have a 1991 jeep Cherokee Laredo with the 4.0L Inline 6 with auto transmission. Recently I have chasing a reoccurring problem after I changed the tranny fluid it will idle betwen 250-750 after it has been put in gear and it will stall out after running for a bit. Sometimes it will run fine then it will stall when I start slowing down to a stop sign or light. Mainly it will stall when I have my foot on the brake. I have already changed the plugs, tranny fluid, air filter, fuel filter, battery cables, and cleaned the carbon deposits off the throttle body.

 

If there was a lot of carbon on the throttle body, i'd suggest checking/cleaning the Idle Air Control (IAC) The pintle and seat can get pretty dirty and prevent a good seal which causes idle problems. Clean it well, but don't twist or pull on the pintle as they are easily damaged.
If that doesn't improve the idle, you might also check the TPS (throttle position sensor) An analog meter on the resistance scale works best.. unhook the connector and put the leads on the TPS. As you move it slowly to wide open and back the needle should move steadily (no hopping around).
Lastly, check for vacuum leaks. They can certainly cause idle problems. Good luck!

 

Thank you it was the TPS sensor I had to replace it! And the IAC sensor was extremely dirty..