Have a 2011 gt
. It has a 6 speed with 3.31 rear gearing. I did a 3 inch flowmaster cat back exhaust, jlt intake, and did a lethal performance 93 octane race tune. My main question is when I roll on the throttle when I get to 3 to 4 thousand rpms the motor acts like it hits a wall so to speak. Really weird. Is this normal? Besides this the car rips and I went on a road trip recently and knocked down almost 27 mpg.