Batterycharger

Just finished installing a polished and ported Throttle Body along with a 4 inch Calloway Honker on my 2009 C6. Can tell a big difference. the only question is that when I simply rev the engine it seems to clip or top out at 4,000 RPM's, but when running it screams. Am planning on a Dyno for the engine and the A6. Is the current setup on the computer just sensing too much air past the MAF and shutting down. I am a newbee and could use some direction. thanks