I had this happen to me when I picked the car up from the dealer after they installed the new engine. It was some carbon buildup somewhere on one of the old parts still in there that triggered the CEL (can't recall where the buildup was). Never had a CEL again after the mechanic took the time to fix it (on the spot, no hassle, this is a Ford dealership...hmm. too bad they're 50 miles away. If anyone's in the area, Huff Ford in Wytheville, Va has my highest recommendation)

Midnight Red '95 Contour SE ATX
Just completed the lighted moonroof switch mod. Its great!
www.webcentrix.org/contour_se.html

"The whole purpose of a car is not to go fast it's to get from point A to B, and if you can afford it, to get from point A to B with some sense of style."
As seen on the Ricecop.com boards