Car stalling/limp mode then won't start again

Your going to have to have the car scanned with a professional scanner because a diyer scan tool can't read steering codes and other codes etc.When the steering light comes on do you loose power steering?

Well crap, I already cleared the code. I will try to recreate the stall and then get it scanned. No, power steering was not lost and there is plenty of coolant in the tank. The engine was running really rough a week ago and it seemed to be misfiring, but it settled down after shutting it off and turning it back on. It has not happened since.

So it runs fine now?Also are you sure the code you had wasn't a P1000?

I drove the car quite a bit today to verify all problems. (This is my girlfriend's car.) While idling with no a/c, everything seems normal. Idling with a/c causes drop in revs and a rough engine. The car had strong acceleration, but seemed to drop revs while shifting with the a/c on. The car shut itself off at 50mph with the a/c on: motor cut out, lost power steering. The dash dinged at me and flashed "PWR STR" and "COOLANT" orange check engine light came on. Would not start for 10/15 mins. Took it to local auto parts store, they read code "U0100".

When it won't start is the security light on solid or flashing with the key in the run position?Also sounds like you can get a professional scan done now with a scan tool that can read codes on all your computers.With ac on at idle what does your battery's voltage read at the battery?With engine shut off does the center of the clutch spin freely?