[Big Horn]

I personally believe a permanent fuel pressure gauge is one of the more important things to have.

RT is way ahead of me on the learning curve, I took his advice in 2018- and I completely agree on the importance of a permanent fuel pressure gauge as a diagnostic tool.


i have some major exhaust leaks, at the exhaust manifold to up pipe and up pipes to collector and I still have OK boost and still get good mileage (avg. 17 empty and 15 pulling 3500# boat/trailer) so I’m not sure that’s you’re issue.

I didn’t notice if it was mentioned - how many miles on the clock?

Up to date on periodical maintenance? Changing gear lube in differentials, checking wheel bearings, checking brake caliper slides and pads for drag?

 

[Big Horn]

she only has 84kmiles.

Nice!

Is this issue with the mpg something that changed at one point, or has the truck always had poor fuel mileage since you’ve owned it?

Have you removed the tuner and ran stock to see if it affects the mpg?

 

[Big Horn]

Anyone saying they are getting 14-20 is just messing with you. They don't and never have. If they insist borrow it and drive it for a tank. I have the identical truck and mods and know plenty of others with the same thing. I drove it on the highway at 70 once and got 11. I'll never do that again. Boring. I get 8-9 mpg and I'm happy with that. Prior trucks had 460 and 454 gas engines and were 4-6 mpg so I'm thrilled. 38 gallon tank at 9 is 342 miles.

Shep,
Welcome to the TDS forum.
You must have us confused for some other Ford diesel forum.
Based on your reported fuel economy, you should stick around and learn some things because your truck suffers from very poor performance.

Yep!

I average 17 mpg on the freeways. The best I ever got was 22 hand calculated. Towing or loaded I can still get better than 10 mpg

Sent from my SM-J737V using Tapatalk

And Yep!

 

[Big Horn]

Fuel economy is not
performance

Ahhhhh, but it is.....and what sells vehicles, and what the trend has been (see graph) Poor fuel economy does not equal Performance:

Performance and Fuel Economy Trends – Internal Combustion Engines