I'd have to agree with Bob. Anyone with experience with CELs in general and Ford CELs specifically can tell you that only in RARE instances are they a major cause for concern and then there's usually some type of performance indicator. I have the CEL problem on my Duratec off and on ever since I've had it (Feb. 98) and it has never been a major deal. It has 132k on it now and, after having the MAF sensor and the EGR valve replaced, the sensor will come on after warm-up and then again, somtimes it doesn't. My 1992 Escort with 140k had the CEL for better than a year straight several years back with no ill effects. If you are in tune with how your car should perform and it doesn't seem up to par, that's a better indicator than the CEL.
