Hello I'm a new comer to this site and have been reading some of your topics. It seems that you have alot of knowledge to the new trucks, so maybe you can help with mine. I have a 2005 GMC Sierra Ex. cab 5.3, 3:73 rear end. I have installed all the bolt ons that I can without the supercharger. I'm having a problem with loss of power. I was able to light up my 20" tires from first gear into second when I installed my JBA headers. One day I was racing and SS and redlined the motor. The motor shut down on me after 6100 rpms, and made a loud sqeal. It still seems to run ok, luckly, but it will not do a burn out now. I took to the dealer and they said no codes came up, so everythings fine. Wrong answer. So i took it a engine builder and tuner. They did everything they could to try and fix it, but they also could not find the problem. They adjusted the fuel and torque management, and said that something seems restricted. Can a new truck get clogged cats this early or my flowmaster breakdown inside? We thought of everything including a bent rod, but no signs of smoke coming out of the exhaust or a fouled plug. Could it be something in the comuter somewhere? A sensor? Does anyone know how to fix this?