The speedo went out on my 2000 a while back and my gas mileage feels like it has suffered. The cluster is good and I have replaced the front vss on the output shaft with no change. Would not having a speedo really effect the way my truck runs or can I just use my gps?

 

if your speedo was off, you may be driving faster using your gps...and getting lower mpg's. Most speedos are showing that you're traveling a few mph faster than you are. Your gps will be more accurate.

 

Yeh I understand the concept there but and I figured in the 10 percent for the difference in tire size. I was wondering if there is no signal goin to the computer if it would negatively impact my mileage.