'03 Aviator still has problems

I recently had the Idle Air Control Motor replaced in my '03 Aviator but it's still running rough. The car runs fine when it's cold but as soon as it's warm and I've been driving for a while the problems start to happen. After driving about 150 miles, I stopped at a traffic light. When the light changed and I started to accelerate the car jerked forward as if the gas was cut off and it was gasping for fuel. When shifting into reverse the car makes a klunking noise and then has a tendency to stall or the idle sputters. It also hesitates or hiccups between 40-50 mph.

Any ideas?