Stalling problem

I have a 1992 Pontiac Bonneville SE. It runs great as long as it stays running. Every now and then it just stalls, no warning it just cuts out and thats it for 10 to 15 minutes before you can start it again. I had it in the shop. He could not find anything. all tests check out OK. He finally told me to come get the car. of course on the way home it stalled. This time it did start up and we got it home. I would say this happens about 1 in 4 times the car is driven. It's a bummer because it's a very nice car but I can't trust it. Any ideas?

Did you replace the crank sensor ? That should be the first thing you try. Also, for a couple bucks replace the fuel pump relay while you're at it.