I initially placed a topic under "loss of power", and I have found a Chevy Dealer, who may have pinpointed the problem but they are not sure. I have a bad Mass flow sensor, and a fuel pump that is putting out too much pressure. Here is the rub, the Chevy Factory Rep stated that since I had a K&N filter installed, they would not warranty the Mass flow sensor, and since I once had performance software installed (Hypertech), that Chevy would not honor their warranty, and they have issued new bulletins to their dealers stating so. Has anyone else had this problem, and if the rep is just side stepping the responsibility, do any of you have something I can show the factory rep. Thanks to all.