Gents....
What type of fuel "economy" would you think a 1991 F-150 short wheelbase reg cab 4 wheel drive with an automatic and a 302 should get? Runing 31 x 10.5 x 15's on it.
I'm getting about 12 mpg highway.
Thanks!

 

What gears?
Which automatic?
It makes a big difference

 

12 is about right, but you need to compare the odometer to a GPS, and read this caption:

 

I'm lucky if I get 10 with my 1994 extended cab short Box. 4x4

 

I appreciate the comments. I need to figure out what tranny and gears I have.
Just seems to me that it got much better mileage when I got it a few years ago.

 

Auto trans (AOD?), gears - check metal tag on differential cover; I receive 12 city and 16-17 mpg highway in my '94 Gen. 1 Lightning with 4.10 gears and 89 octane Shell.

 

What are the TRANS and AXLE codes on the door jamb sticker?

 

You might want to check your fuel pressure regulator. They are prone to fail, especially after 20 years, and can dump a lot of fuel in that engine. If it's pushing more than 40 psi of pressure without vacuum, expect to change the O2 sensors and the cat will likely fail in the near future.

 

Keeping up on yer' maintenance? Might be time for a tune up.

 

I was getting 16-18 highway with my 351 and 14-15 city. Had an E4OD with 3.55.

 

I have a 95 XLT 4x4, 302 auto and am getting 11mpg so far with 178,000 miles.