While driving around town, the idle started going up and down, then the engine died. I turned the KJ off, then on again and it seems to run ok, but the idiot light is now on. I pulled these two codes:

P0123 (Throttle position sensor voltage high)
P1299 (MAP sensor and throttle positon sensor signals don't match. Check for vacuum leak)

If it's a vacuum leak, wouldn't it run erratically all the time, and not just for a few minutes? What else should I be looking at?

Thanks.

lonely....so lonely....

Stupid Jeeps.

For the TPS clean the throttle body out real good,pull battery cables for 1 hour and run,if it comes back replace the TPS.

The second code is more in depth,1st look for any visual broken vacuum hoses,cracked plastic upper plenum.P1299 should really be diagnosed with a smoke machine to make sure there is no vacuum leaks.Having a code reader that displays "Live Data" can help to make sure the MAP sensor is working.Might try replacing the MAP sensor or doing the Seafoam thing through the brake booster vacuum hose and see how that works.

Thanks for that.

I did a visual of all hoses and found nothing. I may look into replacing the map sensor.

I'm doubting that it's a leak because it would run rough and stall all the time, which it's not. Of course I'm just using noob logic, so you never know.