I'm curious too... I have the same vehicle, same tuner, and same problem.

mikel wrote:Its 99% going to have something to do with some wiring that was changed onthe vehicle, likely during the stereo install....

Terrific.. To date I've done all but uninstall everything.. All power has been cut/disconnected to all installed devices EXCEPT my remote start.. Are these known to interfere?

I've been searching this topic for weeks now, and have tried just about everything... And am beginning to get a bit concerned.

Here's a quick history. 9 Months ago a friend was selling his tuner after trading his truck in. We installed it into my (at the time) stock Avalanche with no problems, and ...