1996 F-250 eng light over 50 mph for 10-15 min?

Question

i have a 1996 F-250 with the 7.3l (460) motor. my check engine light is off when i drive in the city, under 50 mph. the light doesn't go on until i reach over (+or- a couple) 50 mph for about 10-15 minuets. but it goes off if i shut the truck off. all my gages are good but I'm worried about the light. i perform all my own maintenance regularly. so i really don't know why this happens.any ideas?

Answer 1

I had the same thing in my F-250 it was told to me by the tech it was due to my gas cap being not tight. this allows air pressure to be lost in the vacuum advance due to this is a closed system for the

carburation to work right the system needs the gas cap to be on flat and tights for the three pumps on the fuel system to work with the fuel

sensors, Ford has not gotten a good rep for tollerance on their electrical sensors the reason ford products have a bad rep of late on

repairs. It cost me 160 dollars for them to tell me at the dealer the gas cap was causing the engine light to trip the tollerances on the sensors

on the fuel mixture due to air entering the mix causing the carb to

have to enrich the mixture i the engine to comp for the leak.

Tighten your cap down proper every time you fill up and avoid the 160

dollars you fool bill. I felt the same way when I moaned about having to pay for 11/2 hours of 90 doallrs a hour labor for a loose gas cap.

funny huh I had the same problms and after I driven into the afternoon mine the light would go out on its own due to the gas tank built up

heat from the sun expanding the fuel in the tank the light goes out.

cheers