My friend's 2001 Geo Tracker 4 cyl auto runs good but after she drives it for a while and stops , it won't start again until it cools down. It doesn' run hot. And it runs okay while it's running. It just wont's start for a while when she stops for a while. She just had a new fuel filter put on it. I think it might be some kind of module that gets warm and shuts off when she turns the car off and won't start until it cools down. Am I on the right track?

I'm not sure where the problem is. I don't think her car has an Ignition Control Module. That function is likely integrated into the ECM (computer). Also, I don't think there is a coil pack--it likely has coil-on-plugs (COPs). Finally, I don't think there is a main relay, which frequently cause problems in hot weather due to cold solder joints on the PCB.

Try checking for any codes. Crankshaft Position Sensors, because of their vulnerable location, frequently cause problems. It's possible the problem also resides in the ECM, when it gets hot.