Speedo Problem After Gear Install & XCAL2 Tune

So after getting pulled over and ticketed for "doing 83" in a 65 up in Vermont on my trip this weekend (when my speedo said about 79)... i realized that i would test my Speedo one more time with mile markers, and I found that it IS a tiny bit off. Sometimes my trip changes before and sometimes after I get to some of the mile markers.

I find when its about 75mph it starts getting off but when i go about 50 its dead on. So im a bit confused here....

I have the car tuned with the Xcal2 to KNOW the car has 3.73 gears in it.

Is it possible that the speedo-gear in the Transmission is throwing it off a bit? Does anyone else have this problem?

CobraRed_96_GT said:

could be a dick of a cop Have some one ride along side of you while on the cell phone with you. IF more problems and you mind the 4.8% diff at 83mph then get a dallas mustang speed call $50 used or so

Click to expand...

I have a Dallas Mustang Speed Cal that i never installed, cause i got my gears installed and then just bought the Xcal2 right afterwards (i had the speed-cal for a long time now anticipating the gears, but changed my mind after the gears were installed). So i already have one... but its NOT installed... just sitting here in my room.

Think the speed-gear in the trans is the problem?

Also.. Can i put a new tune straight throught the Xcal to flash the car? or do i ALWAYS have to re-install the stock tune, THEN install a new tune? I'd rather just keep "overwriting" tunes if i can. instead of reverting back to stock, and then tuning over

bump