Assistance needed calibrating. :/
 

Alrighty, so what I have is a 94 Buick Roadmaster Wagon with a LT1 sequential fuel injection.

So far, I have the MPH speed calibrated, the VSS speed sensor by the OEM says its 4000 Pulse/Mile but I have it calibrated at 7850 for the speedo and Guino to match. but now my MPG is off drastically, its saying at highway speed I'm getting 120MPG, yeah something is off.

Any suggestions?

You need to adjust the µSec/Gallon too.
Adjust it the same percent you adjusted the VSS and it should be good again. (I think, if my monday-morning-math works :))