Saturn L300 Engine Dies, Stalls at Stop, Restarts ok

I have a 2003 Saturn L300. Recently, the engine dies when I am stopped in traffic. It only happens intermittently. Today it stopped while I was moving forward at a modest speed after being stopped. It has ALWAYS restarted immediately after it shut off. I read some of the posts here about the CPS and checking the codes. I don't believe it is the CPS since those folks reported having to wait a long time to start their cars. Also, I don't think it makes sense to check codes if there is no check engine light showing. A couple weeks ago the check engine light was on and I took it to a shop where they replaced the vent solenoid. The check engine light came on again and I went to Autozone to read the codes. I replaced the fuel cap and then disconnected and reconnected the battery to reset. The check engine light has never came back on again. A few days later my current problem started. I'm reluctant to take the car into a shop again since I don't know when the current shutoff problem can be replicated. Also, I'm worried they will start replacing things that may not be necessary and I'm going to end up spending too much money and not solving the problem. Please help! Thank you!