I have the same problem almost 1 tiem a week it happens.
When I change from D to R it makes a sound and after it, the car runs like if it was always in 4th gear no power it acelerate very slow after turning it off several times and reving the engine it works normally.
Have you fixed the problem?
I took it to a mecanic and he said that the computer reads a transmision error that it might be the sensor but he wasn't sure.
Tuesday, November 16th, 2010 AT 2:31 AM