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?

 

Hmm maybe that has to do with that drive by wire set up on the newer ones? what other mods do you have? Im sure "mise" could offer some insight