I have a 1993 Ford F150, 4X4, extended cab, short box, Automatic, with a 302. I just put in a new cap and rotor, new Bosch platinum plugs and new wires, and also put on a new starter in the last month and oil change, I recharged my K&N air filter and the truck shows no codes nor acts or drives funny. My fuel mileage is around 8 to 10 mpg right now. What is happening? According to the books it should be closer to 15 mpg which I can live with. It also has headers to dual straight pipe through glass packs out the back.

 

tire sizes please bigger tires kill fuel milage

 

How many miles on the truck?

Is your 02 sensor still in place? Granted that show should up on the codes.

 

I do have BFG's 32X11.5 on it, but they have been on it for over a year and the mileage was still better until more recently.

 

The O2 sensor is in place and codes are all good. The truck itself has 170,000 and the engine was a brand new crated engine in 06 and has about 60,000 now.

 

depends on tune, oil used, tire pressure, wind resistance, etc etc etc

 

Yeah I've gone over all those details. It uses no oil, and I keep the tire pressure around 45, and it was just tuned up. I also have a 1992 F150 that I am getting over 15mpg in. This is just a weird instance where it seems to have dropped with no apparent changes in the vehicle.

 

any change in driving habits?

 

No, it's the wife's daily driver. We live on an acreage and show horses and so we both have F150's. mine is a 1992 2 wheel drive manual, and the other is a 1993 4X4 Automatic. Our driving habits are pretty much exactly the same. I'm wondering if the fuel pump would be a culprit. The reason I say that is I noticed the lower fuel economy when my front pump just went out recently and am using the rear tank but it makes a constant humming sound. It seems to be running fine and all but I wonder about the constant sound.

 

maybe or could be the fuel pressure regulator or you could have the notorious crossflow issue