The computer will reset after a certain number of "driver cycles" (turning the car on and off). My recent experience with the CEL after a fill-up left the light on for about three days before it finally went out on its own. I guess the stringent U.S. emissions standards and the dirty byproduct of the rotary engine left Mazda no choice...they had to overinstall the sensors. It's a pain in the butt, though. I hate driving with that light on. Maybe the gas caps are faulty. Or you can disconnect and then reconnect the battery, if it comes back on it's more than just your gas cap.