buffgsr

i dynod my car while on dyno everything was fine i did 304 on a mustang dyno ..when i left as i accelerate throght the rpm more so 3rd gear then anything the car sputters like it forcing its way through the rpm....sometimes it does it sometimes it doesnt....but it goes slow...by the way i not running a dumptube on the waste gate and im running chrome program any help would be great thanks