Bad mpg

a lot of good suggestions here - I agree 7 MPG is a problem worth exploring. I get 10 pulling my travel trailer at 65. So, what I would do: jack the truck up and find if there are any drag issues on the brakes, check the MAF sensor, didn't catch it but have you checked your air filter?, run it by a code reader to see if anything is tripped but not lighting the CEL, remove your tires and borrow someone else's stock tires and see how the numbers compare (I doubt it's just the tires though, but a process of elimination), replace you O2 sensors. Take it for a long highway ride to see what numbers you get at steady speeds (eliminating the comments on jackrabbit city driving). Once those things are exhausted bring out the wallet and dig deeper, such as engine or tranny issues. Good luck!

 

Is the check engine light on? Have you scanned it for codes?

Cats can clog without setting codes. Just about any other sensor failure "should" set some kind of code

A code reader with access to short/long term fuel trims would be helpful

 

V6 6 speed 3” lift w/ 33’s and aftermarket wheels. I get 14ish mpg on winter gas.

Something is drastically wrong with your vehicle or you drive like a dick

 

first off your lift, the bigger tires, and you probably didn't rear gear the front and rear differentials. the reason I know this is because I have the same thing.

What you can do to help is inflate the tires a little higher then you usually would but not enough to cause too much wear in the tires.
swap out your 3.73 gears in both the front and rear differentials to a 4.56 or better yet 4.88.
hope this helps!

 

I once has a 1974 Cadillac with a 500 cubic inch engine that got that exact mpg.

 

Dirty MAF?

 

My 71 mustang with the 351 Cleveland got about the same also.

 

Even without regearing, the gas mileage shouldn’t be 7mpg. I’m on stock gears and get 14mpg as posted above.

 

What he said...

 

Pistons ftw.

 

Maf sensor is clean and no lights are on. Have a few things I’m gonna try. Can’t keep driving something that gets 7mpg. thanks everyone for the gel

 

Have you done a sea foam treatment

 

No

 

7mpg something is definitely wrong.

There are a lot of "I get crappy mileage" posts that are "Pilot Error" but yours has merit. Keep slogging through the troll monkeys posting and somebody will have the answer.

I'd guess brakes might be part of the problem but if they were dragging enough to cause a 50%+ reduction in mileage I'd think your wheels would catch fire in about 10 miles.

 

Other person are you sure you are doing the math correctly when computing MPG ? 7mpg doesnt make sense. Do you have a 2000lbs of concrete in the bed, are you dragging dead bodies, are you sure all 4 wheels are still on the truck? All the other crap people are spewing, MAF, sea foam, blah blah, all a waste of time. You must have something seriously wrong with your truck to get single digits.

 

Yes I’m sure the math is right

 

No big gay unicorn sticker weighing it down, right? Hear those things can do a number on a truck.

 

Wheel bearings, carrier bearing, diff, u-joints? Lots of parts can add drag but not throw codes. Heavy tires and wheels can wear bearings faster.

 

E-brake pushed in enough to drag but not enough set on the dash light? yikes thats bad