I recently upgraded to 295 Nitto Trail Grapplers and noticed about a five MPH difference between my speedometer and my GPS at 75 (The vehicle reads 70 but the actual speed is 75). Additionally, my odometer is now also incorrect by about 10 miles for every hundred i travel (if I drive a hundred miles my trip OD says I drove 90). I am trying to find out who can adjust this. The Hummer dealer in Tucson basically said they do not do that and have no idea who does. Any suggestions?

 

you can have it done w/ a PCM tune. I got mine from pcmforless, they run sales on some of the forums from time to time also.

 

Yep pcmforless is about your only choice man

 

Thanks gents, already looking at the order sheet!

 

JUST keep in mind.. a lot of places will void your warranty because of it! And if the dealer ever resets your PCM, your tune is lost!