91 Century Stalls Out

My teenage son has a 1991 Century, 6 cyl. After it running for a little bit 10-15 minutes it begins to stall out but only when stopping or taking off from a stopped position. Sometimes it will start right back up and other times it has to sit before it starts up and wont even attempt to start up. You turn the key and nothing it won't even attempt to turn over. Give it 15 minutes and it will start right up. Did the code test and got a number of codes.

26 quad driver module computer circuit #1 fault
27 quad driver module computer 2nd gear circuit
28 quad driver module computer circuit #2 fault
39 clutch imput circuit fault
42 EST circuit grounded
48 misfire diagnosis

Sounds as if the fuel pump is working good. New fuel filter. Runs fine once it is going as long as you dont have to stop. Hoping someone has some helpful information that don't require me to take it to a garage and spend money that I don't have. Please help. :)

most quad driver and code 42 issues indicate a bad ICM or ECM. Most chain retail auto part stores can test your ICM for you, ECM's they cannot.