Grand Cherokee Starting Problem

I have a 2002 Grand Cherokee, 6-cylinder, and a 4.0 engine 65000 miles. This problem just started this winter. The engine cranks nicely but it won’t start unless I push the gas pedal, then it will start. This has to be done every time, especially when the engine is cold. Sometimes, when the engine is warm, and I try to start it again, the engine starts without any problems, but this only happens once in a while. However, if it is released too soon, the engine dies.

The gas pedal has to be pushed a little for about a minute or two, and then the engine continues to run. The engine isn’t stable when it is idle for the first couple of minutes. I have installed a new idle air control valve and a new starter but the problem continues.

With no codes, you’ve already eliminated the most likely non-monitored suspect, the AIS motor.

A SWAG would say that maybe the coolant temp sensor is giving faulty data, but that should show up on the gauge. The cam sensor controls the fuel trigger, the crank sensor the ignition trigger. Those appear to be functioning. It’s the mixture at cold start that appears to be faulty.

Curious condition.

P.S. One obscure thought comes to mind. The TPS is indicating WOT (engine clearing upon start up) and you set it off of that faulty spot to start it. After starting you’re in open loop until coolant temp normalizes.