What could it be?

Driving home yesterday in my '97 88LS, (86,000 mi.) check engine light comes on. Car seemed OK, so I drive it home & park. This morning I go out to start it and it's now very hard starting & rough idle & acts like it's going to stall any minute. CEL still on, too.

I'll be taking it to the shop next week, but what do you think could malfunction so fast to cause an otherwise smooth running car to run so bad all of a sudden??

Part II:
Before the CEL came on yesterday, I heard some loud grinding noise upon startup. Opened the hood and seemed to be coming from AC comp. pulley. Looks like some fine metal shavings around the pulley/clutch on AC compressor & hadn't noticed that before. Pulley looks to be turning, but still has some noise when engine is running.

Could this be related to the CEL or do I have two seperate problems? :confused:

Speedway gas... lol My runs like crap oin speedway gas. Bc its soo cheapy