Jeep rough idle when cold



On my 1991 Jeep Cherokee, 6 cyl 4.0L engine, automatic, after it sits 4-5 hours (cold engine) starts, but has a tendency to stall unless you keep giving it gas.

The MAP sensor and the IAC idle control valve have been replaced recently. I am thinking it might be the TPS throttle position sensor since it is original and that’s 16 years old. The engine itself is a rebuilt with less than 15,000 miles on it.

Thanks Hal


I’d be more inclined to suspect the temp sensor. The ECU may not know the engine is cold.


Can you be a little more descriptive on which temperature sensor? Would it be the
Air Charge Temperature Sensor?