Trevor Dawson

I have spent some time searching the threads for mpg issues. I see it's a common thing but I really didn't come up with any answers. I see there are people getting almost 20 mpgs no problem then there's other who struggle to get 10. I have a 1996 ford f150 regular cab shortbed rear wheel drive 4.9l 5 speed 3.55 gears 30" tires with 112,xxx miles. Brand new clutch and brand new fuel pump. Alignment is perfect. Just picked the truck up about a month ago, I drive about 20 miles a day not many stops and speed is between 40-60 on pretty much every road. I drive the truck like a grandpa and the thing gets a constant 10 mpgs. I know it should be getting better than that because my 95 f250 5.8 on 37s gets 10 mpgs. Gonna do a complete tune up, change the fuel filter , clean the throttle body, change air filter, and run injector cleaner on this next tank will update. Looking for suggestions on other things that could be causing poor fuel economy. New to forum , think I got all the info I can. Thanks

Hausguy

Welcome to the forum - lots of great info and help here. I purchased my F150 about the same time as you.


FWIW, I'm getting just about 15 MPG on my 1989 4x4 4.9 4-speed 3.08. A tune up should help you.


Good luck.

Trevor Dawson

Thanks for the reply, I should be getting that at least especially if yours is 4x4 . Hopefully this tune up does it of not might need to look into the cats

77Ranger460

That truck was rated for 13/16 mpg when new. I would expect maybe a a couple of mpg more, but not anywhere 20 total....The first thing I would change are the plugs, O2 sensor and air filter. Make sue your brakes aren't dragging and the front hubs are unlocking.

Manuellabour247

A lot of those people that are getting 20ish have done some mods like e-fan swaps. There are things you can do that will free up some horsepower, bit don't expect prius mileage with monster truck power. It's one or the other.

Are your tires standard tires or LT? The LT tires will take a hit on your mpg.

I would recommend a full fluid change to include the rear end. If you don't tow you might be able to flex a little bit with the weight of oil so long as its full synthetic. There's some other tricks in the threads like playing with the timing and modding the environmental stuff.

fltdriver

What I would do and the best order in my opinion to do it in:
*Pull your codes, doesn't matter if the CEL is on or not there should still be codes. Work those first. https://www.f150forum.com/f10/how-re...es-obdi-10907/
*Run your cleaner through the gas, seafoam the engine. Clean the TB blades/edge of TB.
*Then change your plugs, wires, belt, idler/tension pulleys. Check for any pulleys that aren't easy to spin by hand.
*Replace all of the small diameter vacuum lines coming from the intake manifold vacuum tree. Cheap rubber lines available at auto parts stores, for a one and done swap get 22ft of 4mm line from http://www.siliconeintakes.com/silic...686d47fdf65361. Super thick walled silicone that will last forever. Either way you need a 4-way vacuum tee or two 3-way vac tees. Just like changing plug wires, pull one and replace it, move on to the next, you don't need to know what does what, just swap them out.
*Replace wheel bearings, inner and outer. Check for proper brake functionality.
*E-fan, one of the better mods I've ever done, quiets the engine down significantly, simple and fairly cheap when using mopar fan from junk yard and the $20 advance auto/autozone temp controller. FWIW I gained 1 mpg in town and close to 2 on the highway after this mod.

What I recommend to everyone that picks up one of these trucks in regards to basic PMing after they change fluids (don't forget the brake fluid!) and other basic tune-up stuff:

Replace the vacuum lines.

Clean up electrical connectors (quick drying electronic clean -walmart for $4-, chassis grounds (important), and battery terminals.

Buy a 120ct assortment of fuses online and replace every fuse on the truck.

Doing ^these^ three things will save you so many headaches down the road.

scottnbarbi

I have a '96 extended cab 2wd, 4.9l, 5 speed, 3.55 rear end. BFG All Terrain LT235/75/15 tires, K&N cone filter, running 5w30 synthetic oil with 103k miles on the clock. I average 14.3mpg empty over the last 15,000 miles and 9-10mpg towing 3,800 pound travel trailer with 1,500 lbs in the bed.
I had a '94 when it was new and got similar mileage then so I think that's pretty good for being 20 years old.