Hello I have an 89 ford f150 auto, supercab-shortbed with the 351w V8 in it. I was wondering how many mpg am i supposed to get out of it. I am taking the steps to milk it, like driving like a granny and not accelerating like a jack rabbit. But my current mpg is 8 ....... any suggestions? thanks

 

sounds like you need a tuneup- timing, dizzy cap, rotor, plugs, wires, air filter.

 

also check your fluids, axles, tranny, t-case.

 

diddo what he said, if you're running stock tire size, you should be getting a bit better than that. Is it city or highway driving?

 

the tires are 33 x 12.5, but i dont think it would make a substantial change to mpg. It was combined city/highway driving. I am going to give it a tune up, but it hasnt been not shifting to 4th, idk if it is a 3speed, but im sure they stopped making those early on

 

It could be a C6 trans, this body style was the last to get it. It's a 3 speed auto.

 

And the best auto trans Ford ever did make.....

I wouldn't EVER swap out one for a ****ty Ford OD trans.!

They do make it harder on gas for what ever there mated up to, but at least you don't have to worry about having tranny failures as long as you maintain it!

 

Hi,with those tires is it possible that your speedo is running a little off,what i am saying the difference in rolling size i.e. 29" to 32" height 10% slower.

 

Yes it is possible and very likely the speedometer was never recalibrated for the taller tires. Add in the extra rolling resistance of those big tires it does make a substantial difference in MPGs as well.