I have a 4.0L inline6, 2wd laredo that is having trouble idling when it is started from a cold start. When it warms up, it still has the problem until I disconnect the Throttle position sensor. It seems to work perfectly fine with the sensor disconnected but only when it is hot. It has the problems when the PCM is running in an open loop with the sensors and everything but when the tps is disconnected and it is in a closed loop, it works fine (unless you step on the gas. since the sensor is disconnected, the engine bogs down). I replaced the sensor and it ran fine for 60 miles and started doing the same thing the next day. I cleaned up all the grounds and pulled out the PCM to look at it. Other than the rubber that covers the circuits being cracked from age and dryness, everything seemed to be fine. Apparently it has a temperature problem and it is way over-timing itself. The OBD 1 code reader doesn't see anything other than the Throttle position sensor whenever I unplug it.