DIESEL DUMB = POOR GPM

[BNMLUTZ]

K guys. Im new to the diesel scene, so I need some help to improve my mpg. 99 super duty F250 w/ 7.3, only 76000 miles. Everything is stock down to the wheels & tires. Tell me how to get better than 10 pulling a 4k lb trailer and 13.5-14 pullin nothing (note im not a lead foot). Willing to put $ into this. So what first then next etc. Will have bout 1 grrr over a years time. Thanka all-

[westcoaststrokin]

Well I would say intake and exhaust would help. Let the monster breathe and that should help. Other than that I am at a loss.

[sevenmalards]

Yeah, good luck with your endeavor! My '99 is well seasoned, 225k miles and I've never seen anything over 14! Doesn't matter if I'm pulling 12k lb trailer or nothing. I pulled my '67 Camaro from CA to S.C. and back and got about 14mpg.
I don't get it because there some guys on here with '99's and they claim 17-20. If I didn't d such heavy pulling and hauling for work I'd change my gears. I have 4:10's and I'd rather have 3:73's

[99 Red Stroker]

I have an early 99 and was getting 13.5 and at best 14.I installed the Napa air and chopped my Cat and muffler and jumped it to 19.8. I've just checked it once and that was no load. Mine is a 4+4 and DRW. Real happy with the change along with the new sound. I do have 3:73's and I'm sure there is the difference. I haven't had a chance to check mpg pulling yet. I'm sure it didn't hurt Ha!!!!
99 Red Stroker

[Big AL]

You definitely need to keep the fuel filters clean (change every 10K miles). And I agree with the above - get it to where it can 'BREATHE'
Then let us know what's going on.
Also, what axle ratio do you have (just curious)?

[sevenmalards]

Originally Posted by 99 Red Stroker

I have an early 99 and was getting 13.5 and at best 14.I installed the Napa air and chopped my Cat and muffler and jumped it to 19.8. I've just checked it once and that was no load. Mine is a 4+4 and DRW. Real happy with the change along with the new sound. I do have 3:73's and I'm sure there is the difference. I haven't had a chance to check mpg pulling yet. I'm sure it didn't hurt Ha!!!!
99 Red Stroker

Yeah "ha-ha"!
Man, it went to 19.8? While some guys dream of hot chicks, I dream of 19.8MPG:beer2:

[BNMLUTZ]

Not sure what gear ratio. How can i find that info. I will get that F Filter changed. Do have a pretty clean and new K n N air filter in the stock air box. I know this will generate some contraversy(???) but this truck was manuf. in 1/1999 does not have a cat converter. There was some argument on other posts about this but this definately does not have one on it. I also will hack off the stock muffler. Should I leave it straight piped or put on aftermarket muff. Thank you all-

[Strõkër~X]

i get about 13-14 regardless of what im doing.........be happy,


after all you did not buy the truck for fuel Mileage

[BNMLUTZ]

that being true; however if its possible why not make better mpg happen??

[CSIPSD]

Loose the K and N... It will dust your motor in no time. Add a good intake, AFE stage 2, Tymar, or a AIS...

Do a full 4" turbo back exhasust.

Add a mild chip to it and it should put you around 17...