93 trans am keeps cutting out whats wrong?

['93 red firebird]

Hi I have a 93 firebird trans am with the v8 lt1 engine. I am having problems with it just cutting out on me for no reason, and the check engine light doesn't even come on. I took it to a repair shop to get it checked out he can't find the problem, but he thinks that it might be the Optispark distributor. I have read some places that the lt1 engines were having that problem but he's not sure of the problem and I love my car but I'm not trying to spend $500 on a part I don't need.
P.S. if you can find me a new not reman optispark distributor for cheap please tell me. thanx ahead of time