Hi all,

I inherited a 94 F150 from my father in law after he passed away recently. I have been doing a bit of work to it here and there so that my son can drive it when he turns 16.

The gas mileage is terrible in this truck. Maybe 8 - 10 mpg. I put new plugs, wires, air filter, cap, etc and while it is now running great, the mileage is still bad. I was thinking about replacing the O2 sensor. There is no check engine light on at this point. Does anyone think this is a good next step? If so is this a pretty easy job? I think it is in front of the cat?

Love the truck, just need to up the MPG's! Thanks.

 

What engine and trans are in the truck? My 5.8 is tip top and I only get 8-10 mpg city and 16 highway. Usually an O2 sensor will throw a code. Even without a CEL, you can have codes. My 94 4.9 had a handful of codes with no light. There is a nice sticky on the forum of how to check codes without a reader.
As for the sensor, if you want, you can replace it, it's usually between the two separate exhausts before the Y pipe cat. I'd recommend using penetrating oil to pull it out.

 

This has the 5 liter V8. Short bed with auto transmission. I certainly don't get 16 mpg on the highway no matter how I drive. Very frustrating.

 

give it a go. its cheap and easy. fuel filter too.

 

Not at napa they wanted $48 for one

 

Some Napa parts I've found are almost twice as much as OReilly. My clock spring at Napa was $145 but $50 at OReilly.

 

I'm going to put one in. I got 9 mpg today just doing 30 on country roads without stopping.

There is another oddity I forgot to mention. When I fill up the truck, I have to let gas trickle in or it kicks the pump off. Not sure what is causing that. Perhaps it is related?

 

That could be a vent tube. Another thing that hasn't been mentioned, do you have dual tanks? If you do, and the check valve is bad, you could be pumping into the other rank giving you false gas mileage readings.

 

No I believe this is a single tank truck. I think all short beds had one tank?

 

No my short bed has dual tanks