I have a 97 Blazer, the ride is a little rough but is has always run well enough. Today on my way to work the SES Light popped on. Didn't seem to be running any differently than usual, no weird sounds or anything either.
I had an oil change and tire rotation 2 weeks ago. The only apparent problem the car seems to have is maybe a problem with the starter, it makes a hell ton of noise when I fire it up, but it always starts.
Gas cap is tight, other than that I'm not very handy with cars so I don't know what else to do other than take it to a shop and be over charged.

 

First place to start would be to get the diagnostic codes read, autozone will do it for free.