Thanks P/D, it shows P-0336, I read it's crank position sensor. I do have the PowerMax CR, but never had this happen in the 12 years I've owned this vehicle. I did however note that the light came on as I was accelerating and I felt a mild clunk as I was doing so-like the drive train skipped a tooth on a gear. I had just changed the oil in the GearVender's over drive unit, so intuitively thought that it had something to do with that??? Any thoughts, anyone?