Before you start racking miles with the blinky light, go to an Autozone or somewhere else with a FREE code scan, and see what the problem is.
Codes are like rabbits; they multiply quickly, and like to eat holes in your $hit.
Depending on the model year, you can retrieve the OBD II codes yourself. Cycle the ignition key from off to on three times, leaving it on the third time. If you have a digital Odometer, the codes will momentarily post on the display. If you just have a mechanical OD, then the MIL light may flash the morse code version...