Problems starting 90 Buick after car is warm

HELP please!! i am new to this forum (actually found it while doing a search on this problem). This is on a 90 Buick Regal, previously ran fine.

The first time it happened I had stopped at a store after a 45 minute commute from work, ran in, ran back out and car wouldn't start. It cranked over fine but engine wouldn't catch. I came back the next morning and car started right back up...at the time I blamed it on a 30 degree warm up during the day and maybe ice crystals melting in the fuel line or something...the next morning when I started it it was cold again.

Now this just happened again yesterday - coincedentally at the same store. Started fine leaving work, I stopped for no more than 15 seconds (store was closed), and then it wouldn't start again. Once again, the next morning when I went to get it (from the impound lot as some nice tow guy had come by and made himself $150), it once again started right up.

Drove it to work today, and just out of curiousity when I reached the parking garage, I turned it off, waited ten seconds, and tried to start it again - sure enough I couldn't, but I figure by the time I leave work today it will be fine...

Any ideas? I'm at a loss...it's not going to be work I do but would like an idea of what's causing this before a garage tells me I need thousands of dollars worth of work because I know nothing about cars! :)

The most common cause for what you have discribed is clogged air filter(remove and inspect it replace if needed) also could be corroded battery connections check and clean battery connections. If problem continues also could be a problem with your fuel injectors. In this case try to find an auto shop that offers a motorVac service(cost me $75) this will clean fuel injectors and fuel rails to get rid of carbon build up this is more likely if your car has higher mileage. I hope this helps.

My 94 had the same symptons and it turned out to be the crankshaft sensor malfuntioning as engine heated up. Got it replaced and it has started problem free for over a year.