2003 Elantra Cam Positioning Sensor

Need Help!! My husband is working on a 2003 Hyundai Elantra GLS for his sister in law. While replacing the timing belt last weekend, the cam turned. He got it repositioned properly and it runs however, it then threw a code stating that the cam positioning sensor was bad. While driving the vehicle on the freeway, it exhibits little power. You have to floor the vehicle to get it to accelerate beyond 40 mph and then it lurches from 2000rpm to 5000rpm then drops just as rapidly. You must maintain the pedal to the floor to keep the car moving.We have purchased & replaced and now the new code states that the cam positioning circuit is bad. Cam timing has already been checked. Any suggestions are greatly appreciated.
:banghead: