Why do i have bad fuel mileage

Are you running large tires/wheels? That will throw off your odometer.

I’d start using the Fuelio app. Great for tracking mileage. Fuelly is pretty antiquated imo.

 

I rarely drive that fast but when i do i think so idk from the top of my head what the rpms are at when i drive at 65 mph

 

Im running 265/75r16

 

I work at a shop and when i was showing my coworkers my truck i dont remember exactly what he said but i think he said that when they probaly messed with the head i think either messed up timing or something else but he said it wasnt a big deal so im not sure if thats what he said

 

What does messed with the head mean?

 

Like they took it apart is what his guess was when he heard it

 

This is what one kf the spark plugs looked

 

What brand are those? The ground electrodes look more angular in profile and bend than the Densos I always used in mine. Just a note, always use Denso or NGK if you don't already.

Also, not the cleanest burn. Cinnamon is OK, but that looks rusty. I'd pull them all, see if they are all even tight when you pull them, and index them to each cylinder.

 

Are the coolant and oil both "clean"?

 

I recenly did a coolant flush and the oil looks clean might change it in the next 1000 miles

 

I think they might be ngk not sure and they coils are oem

 

Well whatever they did with the head needs investigation, as does every system disturbed in working on the head.

 

Looks ok to me. Hopefully someone else can chime in..

 

Could also do a compression test. Easy to do. Search YouTube if you haven't done it before. Amazon has many testers available for a decent price. You could also check Facebook marketplace

 

Like a couple others mentioned. Do a real mpg test at the next fill up or the one after if you haven’t reset your tripometer.

1. Fill up.
2. Reset your tripometer before you leave the gas station.
3. The next time you fill up record how many gallons of fuel you just out in the truck. Record the mileage on the tripometer.
4. Divide the number of miles on the tripometer by the number of gallons.

See what that mpg calculation is.

It could just be your fuel gauge is messed up.

I have a double cab 4x4 3.4 with 265/75r16 tires and get 18 mpg mixed city/hwy.

What are your wheel and tire specs? How much do your wheels weigh and are you running e load tires? Mud terrains? Etx