I just bought a 98 M3 Coupe, with a few aftermarket parts, and it has been driving great for the past week that I've had it. Yesterday, I filled it up (with premium), and about 15 minutes later, the Check Engine light came on. I pulled over, turned off the car, then turned it back on, and it was gone. When I went to start it for work this morning, the light was on again. I read somewhere that some cars will flash this light if the gas cap isn't on all the way or something like that? Hopefully, it's something small like this, but what else should I do?
Like I mentioned, I just bought the car, it had been fine for a full week of driving - and now this happens after I fill the tank. (I didn't put diesel or anything in there