I bought a new power programmer from a individual last night. Its a few years old, but never was used. It will let me do everything except up the firmness of the transmission. When it asks me if I want to change the firmness, select Y or N. I hit Y and it goes into loaded the changes into the computer, not allowing me to change the firmness. Does anyone have any ideas? This is on my 00 Chevy Silverado 5.3

 

Sounds like it is a simple preset option, where it adds a certain amount of line pressure when you select Yes.

If you're looking for a little more from a handheld tuner, check out our Predator, U7198 for your truck.

It offers tons of adjustability, and supports custom tuning if you decide to go nuts in the future....
Predator for the 00 5.3 Silverado