I got 3k miles on my 2007 and noticed I had people on my behind all the time. I gps the truck and at 60mph, I am really doing about 57.8mph! The truck is going into the shop monday to see if they can recalibrate it. Anyone else seen this or know about it? Also the trip meter mpg display thing overhead is off by about 2 mpg, I am guessing it may need reflashed or it may be related to the speedo issue? Anyone have any input?

 

The overhead is about 2 MPG off, other's vary. I noticed about 1.2 on my GPS. ODO was correct.
Keep us posted on what you find out.

 

My Dad's 07 5.9L 6spd is off by 4-5 mph NOT in his favor, says he's going faster than actual. Gps verified.

 

just cross-checked with gps this morning on the way into work...within a needles width anyway. Odo is right on too.

 

Most speedometers on most vehicles are a little slow, from my experience.

 

Well, the odometer wont be on if the speedo is not calibrated. I work for Saab as a Tech, we have issues with guys who change wheel and tire sizes. I had to reprogram a 9-3 2 months ago cause his speedo was off 4mph.

Basically your odometer will turn about .1 miles more for every 8 or 9 miles you travel if its off by 1 mph faster. So I would have everyones recalibrated, your getting unwanted mileage on your trucks.

 

You've answered your own question!
Your truck may be programmed for different size tires than what you actually have.

 

This may be true.

I think I am gonna complain about the speedo, the mpg display thing, and ask them if there is a better fuel economy reflash for the truck.

 

I second that......

 

Well, all my cars have always had custom wheels and tires and I had a programmer. SO I drove the truck or car with the gps and then programmed the speedo to match it exactly.

In my opinion, having it 2.2 mph fast is gonna put a lot of unwanted miles on the truck, and should be messing with my actual fuel mileage numbers and mpg display.

 

Let us know what you find out...

 

Hey Ski, did you find out anything?

 

I'm running 285 Toyos on my '07 which manufacturer states are 32.7" tall. Using Smarty and trial and error,I finally set the ABS@32.3" to make everything within 1%.

 

Mine also reads 2mph faster than actually. Figure I'll be right on the money if I upgrade to 285's.

MikeyB