boostnut

iTrader: (7)

A buddy of mine just picked up a nice 05 2500 4x4 ext cab swb that is getting a whopping 9.5mpg average (mostly country road driving @ about 60mph). So whats the trick to squeezing more mileage out of these? Does it take a tune & exhaust upgrade to pick up 2 or 3 mpg or am I dreaming? I can't believe my 2000 1/2 ton 5.3 will get nearly double his mileage, there has to be a simple explanation & solution. Right?

BlackGMC

iTrader: (31)

comparing your 1/2 ton to the 3/4 ton truck is like comparing apples and donkeys.... the gearing is alot different, the weight is alot different, etc.

boostnut

iTrader: (7)

Thanks for the help. I'm aware there are significant differences in the 2 trucks but not enough to drive the difference in fuel mileage (in my opinion). Is 9.5 mpg "normal".

BlackGMC

iTrader: (31)

do a search, there was a thread on this same topic about 2 days ago. 3/4 are not known to be MPG freindly...

boostnut

iTrader: (7)

Read that one already. Learned that one should check his tire pressures and not worry about his air filter. It was mentioned by 1 person that a tune may yield an additional 1 mpg. Still looking for more info.

GMCtrk

iTrader: (27)

I think it's just the nature of the beast. I have a 6.0/4l80e/4.10s in a half ton, a lighter configuration than your friend's HD, and I can't for the life of me get any more than 16 mpg out of it on the highway with the cruise set to 65. The second it goes up around 18% TPS and higher the mileage goes down below 11-12. In town I see around 6-8 mpg on the EFI live real time MPG PID. There's still some tricks like lean cruise and DFCO which can enhance mileage, but regarding the lean cruise I find it essentially worthless....the drivetrain/weight takes so much power to move along that you never get into the cells which would active the leaner AFR. And DFCO reportedly works pretty well, but with my cam, getting it to go into DFCO is taking some work.

Bow-Tie-Beast

Has his truck had a recent tune up? Plugs, all fluids etc. How big are the tires and rims hes running? There are a lot of things that can cause bad mileage.

boostnut

iTrader: (7)

Not sure if he's done a tuneup. I'm assuming you're implying a plug & wire change along with a new air cleaner. Anything else normally performed during a tuneup on a 60K mileLQ4?

Tires and rims are stock sizes.

GMCtrk, thanks for the feedback. You're obviously experienced with this, efi live isn't for newbies (like me). Tells me the tune won't benefit much, I guess they're just heavy pigs that can't pass a gas station.