Originally posted by deldorado
1. Made sure the gas cap was on really tight ( I read that on here)
The tank is pressurized when the motor is running. A loose cap would keep the tank from pressurizing properly.

2. Put the platic engine cover on tight (it had come loose on 2 sides)
There is no way the engine cover coming loose would affect anything. The cover's function is only cosmetic.

3. I took a cloth and wiped down the engine and around.
Unlikely that would do anything... I mean perhaps debris and grime could cause an electrical short somewhere, but not likely.

Whenever the check engine light comes on, a fault code is registered in the vehicle's computer. The only way to know for sure what the trigger is is to have the computer scanned with an OBD2 scanner. You can have it done at the dealer, buy your own scanner tool/software... or, as some have mentioned, some auto parts stores can scan the ECU for you.