07 GT,automatic. Just installed the Flowmaster Axle-back kit and it sounds sweet, but 2 days later I began to notice a loss in power, but I'm sure if its related to the exhaust change. Whats happening is while I'm accelerating and I reach 40 mph the transmission shifts and I get a load groan and the RPM goes to about 1700. I continue to press down the throttle and I get almost no response or just a little response. The only way to get out of that is either back off the throttle and re-apply or just slowly bring it to wide open throttle which would force a shift to get back the power band. It always has done this on occasion but now its worse after the exhaust install. 1 other note, I have heard people say that exhaust clamps alone without welding is a bad idea. And that a leak can develop at the slip-fit connections, could that be why for loss of acceleration/power? And can a leak there actually rob power?

Flowmasters reduce power from what i hear

I would check the O2 sensors. May need a re-tune also 'cause the computer is still programmed for the old exhaust system.

THE COMPUTER TAKES about 7-10 miles to cycle and grab the power after that there shoudnt be any problems if there is take it back to the dealer

choke masters is what I like to call them... they do sound good on mustangs though...