Check Engine light again!

[RIC-H0]

Alright...
My Check Engine Light has come on again!
This is the 3rd time in the last few months that it has come on. According to Onstar, it could be an engine problem or a transmission problem (What else is there!?!?)
I mentioned the gas cap issue, and they said "Oh yeah" that could be it!
They then said just be sure to get it to the dealer within 7-10 days
I've had the gas cap replaced, and the breather tube(?) cleaned out before. Lets see what it is this time!
My service rep was very accomodating about me coming in, and he even tried to troubleshoot over the phone(But, been there/done that!), so he will run a diagnostics check on it while on my lunch break tomorrow to see if they can figure it out.
I'll let y'all know what comes of it.

So, off I go to the dealership again...

Ric-H2