90 cherokee 4.0 need help !!!!

I got a 90 cherokee 4.0 auto tranny that starts missing and losing power when it reaches operating temp. i have to feather the throttle to get it home.When its cold you couldnt ask for a better running jeep having 215,000 miles.

Heres whats new fuel pump n filter,timing chain n gears, map sensor, o2 sensor, plugs wires cap rotor. The iac was cleaned and does work properly. The throttle body was removed and cleaned and new gasket at base. no cat conv.:banghead:
Please help this is wifes jeep!!!

I would think that the IAT or the ECT sensors are acting up. I think I would lean toward the IAT(intake air temp). This tells the computer how rich or lean to mix the fuel depending on the air temp entering the engine. Also the ECT, a 2 wire sensor located by the DS engine mount could be giving you issues also, this lets the computer know when the engine is at operating temp(190-210). Other than that check for vac leaks around the intake.

i have a 95 jeep cherokee which had the same problem..after running for a while the thing would just miss and turned off by itself..i would crank it and nothing would happen..i changed the crankshaft position sensor and that fixed the problem..part came out to be like 50 bucks and did it myself..the CPS is located on the Driverside bellhousing of the transmission, up toward the top of the bellhousing.
good luck!

air temp and ect sensors do not cause misses hot.
This sounds ignition related. You have the crank position sensor (most likely culprit), ign module or ign coil in the coil module assy, wire terminals, or possible ecm (rarely)issues. You also have distributor cap and rotor to look at. There was a bulletin about ignition crossfire hot that can do this too. The trailing tip of the rotor needs to be .050" PAST the term for Number 1 cyl at #1 TDC if the distrib is in correctly. the fix was to trim the dist lock tabs and reset it manually to this spec. You'll need an old cap to open a hole to measure.