4.0 stalls After a moderate amount of stop-and-go driving

[yatesburger]

After a moderate amount of stop-and-go driving and after the vehicle has set for about 5-10 minutes, I'll start it and it acts like it's flooded or missing on at least two cylinders. If I try to drive it, it acts like a bad fuel filter (no power, no load or high revs). Let it cool for about 10 minutes with the hood up and everything's normal. Codes stored were P0303 and P0351 pointing to an ignition problem. Internet search suggested that it probably wasn't the coil rail and suggested adjusting the cam position sensor and checking all connections to the coil rail and cam and crank position sensors. I've broken and reconnected all connections, they look fine. I haven't used my cooling spray to test individual components to see if I might have a heat sensitive coil/sensor/whatever. I haven't tackled the CSP adjustment yet... my Haynes manual isn't very clear on how that's done. Thought I'd get some feedback first. Advice?

[Care Bear]

Howdy John!

[mdfowler]

I had a similar problem years ago.  The signal from the crankshaft position sensor was failing after the motor heated up, as it cooled, it ran fine.  I tested the resistance with the sensor off the jeep, put it on my stove, and as the heat increased, the sensor completely failed, resistance fell to zero.  New one fixed the problem.

Good luck!

[GURU]

Try cleaning the crap out of the throttle body.  4.0' s are prone to excessive carbon build-up in the t-body.  Just take some good carb & choke cleaner with the straw and get inside all the holes and bore of the t-body

[yatesburger]

Thanks, guys. I'll both test my sensor and clean the TB ASAP so I can check it out when it really gets hot again.

[bradrenea]

I had a similar problem with one of my XJ's. Turned out it was the wiring for the injectors, but it was not at the plug. Somehow the wires got hot and melted inside the protective tubing. It would only act up when it got hot under the hood. Took forever to find it!