The first time I ever got a CEL was the day we installed my DMD. Not really sure why. I was revving up the engine 5,500-6,000 rpm when it came on. When I got home that day I unplugged the battery for 5 minutes and let it reset. There was no CEL recurrence for about 4 months. I think it is now due to aging plugs/wires @ almost 70,000 miles.
