Thanks BK. I really like this truck and don't want to prematurely break it. I was told the use of a programmer will void the motor warranty. Even if you return the motor back to stock settings prior to takeing it in, a GM programmer can see the trucks stock programming was changed.
THey tell you this but i have yet to meet one who can really do it!
As far as i know the only thing they can see is amount of times the ecm was flashed and even then it takes more than you everyday shop mechanic to figure it out!!!!! Just make sure it is stock when you take it in as if it is still tunes they can see thet it is running on different tables in the ecm if they scan it!
It hard to say how much rattle is ok and how much is not ok, if you think its totally to much you might want to send the tuner in, but it is normal to get more rattle with each power level you add! The rattle will probally be worst at about 22 2400 rpms under light throttle as this is when the pilot injection shuts off also!