Hey guys, In september I bought a 1994 ford f150 4x4 super cab with a 150,000 mile 5.8l and automatic. It has the waldoch conversion. Now, It is not getting the fuel millage that i was expecting. The best i have gotten is 240 miles out of just shy of 17 gallons of gas. so, I am in search of at least couple more mpg. It is completely stock. it has 3.55 gears according to the window sticker. Will a K&n anything help? dual exhaust? single exhaust with a flowmaster 70 series? I do know it's in need of a tune up due to a twitchy idle. any help will be appreciated.

 

14 in town? I consider that pretty good for that truck(4x4, auto, 351).

I just put shorties and true duals on my '89 302/aod/3.55 2wd truck. I haven't had the chance to get a road trip to see if it increased mileage on the highway. Around town it's about the same so far, around 14. Completely stock,130K miles, including air filter.

 

That's 90% highway. I drive 60 miles roughly round trip a day for work and school. i set cruise control at 60. Forgot to mention that the front hubs have been changed over to manual hubs by previous owner and they are in the free position. it has Highway tires on it.

 

What size tires are you running. Ive got a 96 4x4 supercab with 351 and an automatic and lockouts. Im running 32" tires and im gettin 18 on the highway at 75mph

 

stock 235/75/15's.

 

Ya it helped me when i changed to 32"s on the highway. And i haveant really noticed much difference in town.

 

so just by going from 235/75/15 to 32" tires, your mpg went up?

 

32x11.50s?

I was thinking about running this size until I lift my truck.

 

Ya on the highway. Its basically giving it a taller gear. And with the 351 it still has plenty of power

 

There is generally a tipping point, but at highway speeds, a larger tire

Will let the engine turn at less RPM. "saving fuel".

 

at 60 mph, i'm turning just under 2K.

 

i just noticed that you have a 96. You have a sequential efi where i have a speed density efi system. Sequential gives better mpg's due to better fuel metering.

 

Yup, if you can drop RPM you'll save gas..........up to a point of using more power to move the "brick" through the air at higher speeds.

 

Read over the thread in your other conversion thread.

 

14mpg isn't bad but not exceptional. I would not suggest larger diameter tires if you live anywhere that isn't flat in all directions, 3.55 gears and only 4 forward speeds produces a lot of downshifting on hills and that kills fuel milage. The single best thing you can do for milage without going inside the motor is fit longtube headers and a single 2.5" exhaust system(mendrel bent tubing), if you have a muffler shop create it then 3" tubing produces the same result after factoring in the compression bends.

P.S. What does a waldoch conversion look like on a pickup?