erratic shifting and buck when it goes over 3000rpm.l

This 2002 Ford Taurus is owned by a friend. He had it analyzed by a mechanic using a blue tooth analyzer made by SnapOn. The problem didn't show up as it only would set a code if the vehicle had exceeded 2500rpm. But, what did occur, was the TSB's on this year vehicle were checked and this problem was written up as a bad cam synchronizer. My friend bought and installed the magnetic sensor that goes on the top of the synchronizer. This fixed the problem of the car wanting to buck in and out of gear at 3000 rpm when going up a hill and automatically down shifting since it was on cruise control. I looked at the part he removed and seen there was a brown powdery substance all over the inside of the sensor. I suspect the substance was magnetic in nature and was reducing the magnetic field to the coil that was in it. He bought a new sensor when in my opinion all that was necessary was to clean the powder from the inside of the sensor and the magnetic contact and replace it whereby saving him $35.00. This is no guarantee the cam shaft synchronizer is going to go bad as the powdery substance had only one place to come from. So at best, I believe this to be a short term fix to an inevitable problem.