speedometer calibration problem

[soutthpaw]

Ok this is weird, I used to be able to adjust tire size and get a corresponding response from the odometer... but now it won't do it... also tried changing the tire size with AE and having the chip disconnected and set the truck to stock... it is showing about 4mph faster than actual regardless of the vehicle speed. as compared to my tomtom gps.... I tried changing the pulses per revolution to 20 on one tune too and that didnt work either.....
If the wife gets home soon I am gonna try some other stuff and also run the live data on AE to see what the MPH shows that way