Alright well I got a Superchips powerpaq on my 2003 1500 HD 4x4 6.0 and as of a few nights ago I got a message after i altered the tuning a little bit that said Reduced engine power! Ever since then the truck has been idling real rough and at about 500 RPMs and when I put it in gear the truck practically wants to die. It basically runs like complete ****.

I tried putting it back to the stock programming and checking to see of the code popped back up and then only time the message comes up is when I change the tuning even if it from performance to stock. I even tried putting back to stock and bringing it to the dealership and they hooked it up and said that they couldn't find any codes and they test drove it for two days straight and said it was running fine which is total bull****. Does any one have any suggestions on this at all.http://www.gmfullsize.com/forum/images/smilies/boti.gif

The reduced engine power is something that will always show up DURING tuning.
If the message is there AFTER starting the truck then I see a issue.
If so, I would watch all the power consumming items on the truck (shut them down) and try it again.
Ron

Can also be a TPS problem if it has drive by wire (no throttle cable)