Hey everyone. I have a 2011 GT500 with a 2.5 pulley bbk throttle body and vmp heat exchanger. I took it to get dyno tuned because it was running super rich. I got it back from the tuner and now it has, what I'll call, a surge at part throttle under load. It only happens at lower RPM more prominently in 4th-6th gears. Anyone have this problem before. The guy tuning my car says he has no idea why it's doing that. He put it back to a stock ford tune and started tuning from scratch through SCT. Hopefully I can get some help. Sorry for the terrible video quality got destroyed with resizing and converting to gif