I was having issues with truck. Took it to friend at dealer after returning programming to stock. He said he did some messing with computer. Not sure what he did and to what extent. Now it seems to be running well.
Question is, if I download the 70 hp tune back to it, will it ruin what he did? My guess is that you need more info. as to what he did, which I will know later tonight. Just in case I posted this question anyways.

Moved to 4th gen electronics.

I was having issues with truck. Took it to friend at dealer after returning programming to stock. He said he did some messing with computer. Not sure what he did and to what extent. Now it seems to be running well.
Question is, if I download the 70 hp tune back to it, will it ruin what he did? My guess is that you need more info. as to what he did, which I will know later tonight. Just in case I posted this question anyways.
Did he just update your stock truck tune? More info needed? The way a programmer works. It will take your truck tune put it on the programmer, when it loads the new tune in the truck. When you return it to stock you put the tune back on the programmer & the stock tune back on the trucks ecm...