Engine Performance problem
1997 Ford F150 V8 Four Wheel Drive Automatic 126404 miles

Several times my check engine light has come on. It will go off without service, but for some reason I seem to get better fuel mileage out of it while the light is lit. It does not stay on very long. I cannot see or feel a difference while the light is on though when it's off, the engine does seem very slightly sluggish. I'm not sure whether this is something to worry about or not. I know that little things can turn into big things if they are let go. Please help. This is my only transportation and I can't afford to have it down longer than need be.
Thanks.

I think the best approach would be to wait till light comes on again and stop by your local Autozone and ask them to check codes for you. then come back to forum with diagnostic codes and they will have a better chance of diagnosing problem with much better results.

The light is on right now. The only thing I see wrong at the moment is that there is a hesitation, whether it's in gear or not, when I hit the footfeed. I get a delay when I hit the gas to take off from a stop or when I hit the gas to pass someone. I don't know anything about the maintenance on this truck other than what little I've done to it since I've had it. Not sure whether it may be bad tune up parts or O2 sensor. A vacuum leak perhaps. Since the computer controls spark advance rather than having a distributor, I can't adjust that which would leave me thinking O2 sensor, except that I don't smell the extra fuel in the exhaust that would be the computer's answer to the problem. The only downside to trying to trace down a vacuum leak if that's the problem is automaker's insistence in so many vacuum lines. I'll try getting the coeds run and see what they say. Would be nice in a way if the truck were a bit newer electronically. The newer computer systems in vehicles will tell you specifically what part is faulty rather than saying that the problem is in a certain circuit. Takes the guess work out of it that way rather than taking it to a shop and replacing several parts before getting the right one rather than going directly to the right one first.
Anyway, hope this helps someone figure things out.