Mine did that and it was a plug wire. I went ahead and got 3 new ones and just replaced them. Of course I had to disconnect the battery for 5 min for the light to go back off afterward. I also had to replace a vacuum line from behind the battery (if I'm thinking right) but that didnt affect performance in any way just the light came on again. It costs me like $40 for a computer check, so I do those sparingly.