My engine light comes on all the time for a day or two. It usually comes on 3 miles after a fill up. This morning it came on while driving on the highway with about 1/4 tank of gas. I had the code read and it was a cylinder 1 misfire and catalyst. That's what the dude from Autozone told me. The truck doesn't ever run different with the light on. I'll just ignore it and it will be off in a day or two.

99 Sportage 2Dr, 1.5" body lift, 30x9.50 Cooper M/T's, high lift, CB, custom bumpers, Warn manual hubs, Tom Tom GPS, snorkel.
99 Jeep Cherokee 3" lift, 31" mud terrains