Shan

I was getting my tire size correct in my tuner the other day using a GPS to tell how fast I was going. When I thought I had finally gotten it perfect I remembered that my vivid linq has a digital speed gauge. So I load it up and find that when my manual gauge is straight up and down at 70mph my tuner is telling me I'm going 68mph. I'm assuming here that the tuner is reading what the actual truck is reading and that the manual gauge is just slightly off by 2mph but I wanted to get another opinion on the situation.

Shan

Hm, guess I should have mentioned the 5.0 and ecoboost in the same post as to draw some attention first. lol

leftovers

I have a 2011 Ecoboost with a superchips tuner and I have the same situation. I found that I could get my odometer and engine gauge speed synced with the gps and my manual speedometer still be a couple mph fast. I can live with it but can understand how it's frustrating.

I think it's a calibration issue with the truck, not the tuner.

Shan

Well its not really frustrating... I just wanted to know what the truck was actually reading to make sure its calibrated correctly. As far as the manual gauge showing a 2 mph slower its really no big issue since I know its off.

noid1037

I think others need to see what speed they are doing. I use my cellphone (Droid X) mounted in CarDock mode and it will show the speed Im doing. The cellphone with GPS would state I was driving 70 mph and the speedo on the F150 Ecoboost SCrew would say I was doing something like 72-73.
I used a second stand alone GPS unit and it was in sync with the Droid X cellphone as the speed of 70mph.

How about some other people with information on cellphone GPS speed and truck speedometer?

The truck has 1200 miles on it with Goodyear tires that came with the truck.

I let the dealer know today of my suspicions that the speed is not correct on the truck speedometer. I will let ya know what the word is.
Thanks.