Bad MAP sensor?

I am getting an engine code stating improper air fuel mixture, the jeep starts up then rpms slowly drop down until it stalls. this will even happen when driving down the road. Any time I'm off the gas the rpms drop to about 6-700 then slowly drop from there until it stalls. It will also not climb in rpms over 3000 at which point it will act like its on a rev limiter. These symptoms came about shortly after a pretty good mud bath but no mud got into the intake just a little in the bottom of the air box.

Check the plugs, plug wires, cap, & coil wire to cap making sure they're clean and uncontaminated. Also take a look inside the distributor. If any muck got inside, it could have contaminated the cam position sensor.
To check if it's either the MAP sensor or the TPS, try unplugging the connector to each (one at a time!) and see if the symptoms get worse. If they don't, you've found the problem.

Its a 2000 so no distributor

I just changed the map sensor and it idles and runs at normal rpms but still hesitates and stumbles on acceleration but it is driveable

Have your throttle body cleaned. there can be dirt in the Idle Air controler which makes it not operate correctly. You did not say how many miles on your XJ but on my 86 mustang I ended up having my throttle body cleaned every 30,000 miles. To do a good cleaning they remove the throttle body, clean it, and reinstall with a new gasket.

Also when my dealer mechanic does the job he hooks up the test set to make sure everything is working correctly.

Take it in, pay the 1.0 hour of dealer labor and get the throttle body cleaned.

Natural Ice said:

Its a 2000 so no distributor

I just changed the map sensor and it idles and runs at normal rpms but still hesitates and stumbles on acceleration but it is driveable

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In that case check the TPS. Pull the wiring harness connector off the TPS and see if it runs any worse. If it doesn't, the TPS may be shot. Check the output voltage from the middle wire. It should be 0.7-0.75v with the throttle closed and ramp up smoothly to about 3.8v at full throttle (ignition on, engine off). If there are any troughs or spikes in voltage, replace the TPS.