i have an 06 extended cab 4 wheeldrive duramax i have an hypertech hyperpac a banks ramair kit and a magnaflow turbo back 4inch exhaust kit on it. the truck has run 14.84 in the quarter but it did not have the exhaust kit or the banks kit on it then. i keep getting a code saying that the egr valve is not working right, it has been replaced once and now its doing the same thing that it was doing before the dealer replaced it. it just wont run like it used to. i took it to the track last weekend and the best it would do is 15.86. if someone could help me i would appreciate it.