Greetings, getting things sorted out here to head back stateside. Be another two weeks before I call you for that beer. Check your IAT to see if it is sitted properly in the air inlet, I also took a little time to make sure it was aligned in the tube.

 

If you never had the tire size re-calibrated in the truck and put bigger tires on it, then the truck is incorrectly recording the miles driven. After going up 2 tire sizes my speedo was over 5mph at 70, the speedo would read 70, but I was actually doing 75. That means I would drive 75 miles, but the truck would only log 70 on the odo. I would check to see if your speedo is off with a gps or something, cuz if it is then that could hurt the mileage calc.

And +1 to whoever said calibrate the TPS, when I cleaned my TB the rpms would jump around like crazy till I re-calibrated it.

 

Yeah, I went from 245-70's to 295-70's, so not a huge difference, but enough I guess. I used a calc, I think posted by Jon or Jay, that said I was off by about 7mph, roughly of course. I'm guessing thats a dealer fix, since I can't go the tuner route as of now....

Is that what it would take, a StarScan computer? Or could a Snap-on diagnostics computer do it? I doubt it, that'd be too easy for me, lol. Then I could just get the ol' man to do it for me, his shop has all the new fancy Snap-On stuff....

Thanks for the help again guys, I might just do the "tricks" tomorrow, for the hell of it. I have a 1/2 tank right now, so I could tell enough of a difference with that, if there will be any.

 

A diagnostic computer couldn't do it, like at autozone. Your best bet is a tuner.

 

First of all, forget the O/H console. The only way to properly determine gas mileage is to fill it to the brim (not pump cut-off), drive it, fill it to the brim again. Then do the math. And yes, tire size will affect the apparent miles driven.

 

Thanks Mike. As Ive said, I take the O/H with grain of salt. I filled her to the brim, which then I know its 26gallons in there, no matter where I started filling from. Ran it down to the lowest possible point, did the math, 9.6mpg's, rounded up

 

Your new tires will throw your speedo off by 8.29% which as noted above throws your odo off by the same amount. Then you figure your rear-end ratio is changed to 3.60 if you have 3.92's so your making more work to get moving in town. Try adding another 8% or so to your mileage when calculating. I called a dealership about getting a speedo recalibrate done for my tires and it was $50 so I just went with a superchips.

 

Ouch! Mine isn't that bad even when I go play! Do you have a GPS? It will be more accurate for distance than your odometer. The larger tires will make the odo read lower by around 9%, but adding 9% to your mpg doesn't help much.

BTW, filled to the brim is likely more than 26 gallons. A Chevy 1500 I had with a 35 gallon tank held 37.3 when filled to the brim from a sputtering stop.

 

Haha, that just makes things worse!! A 28gallon tank going 250miles is only 8.9ish mpg! Thanks!!

Ill get over it, just sucks, quite literally!

 

I have a 2004 quad cab 4 x 4 with the 4.7 and i find it really decent on gas. I get anywhere from 500-600 kms on a tank. Thats like 320-370 miles per tank. I have 265 tires on i don't drive it too hard though.