I have a 2001 L with a diablo chip. The Service Engine Soon light started coming on. It would come on and stay on for a few weeks and then go out for a few weeks. I removed the chip after disconnecting the battery and left the battery disconnected for 12 hours before reconnecting it. After driving for about 30 minutes the SES light came back on. The truck is stock except for a K&N replacement filter and the chip.

ANY IDEAS?