I rebuilt my 98 cobra and vortech supercharger, put them back into the car and now at 3200-3400 rpms it will stumble even with the knock sensors off. It runs great everywhere else. I did put deleter plates on it an got rid of the egr. The MSD and computer checked out and I had put all new sensors on it. All grounds were redone, the coil packs checked out and I put another set on for good measure. The tuner turned off the egr and plates. New wires, plugs and 6 months searching. Please throw out any idea