We have a 2004 Ford C-Max automatic and we have been experiencing loss of power on acceleration from first gear through the gears, and when accelerating at about 50mph the car dramatically loses speed and gains very high revs. It seems that it does not change gear and maintains the high revs until the accelerator is released. The car does not like inclines and loses speed and power, but the speed will increase on downward slopes. When the engine has been switched off for a while, the car will then sometimes drive and accelerate with no problem but then all of a sudden the acceleration will disappear. The engine light is now continually showing. Our local Ford dealer have been in touch with Ford and as recommended replaced the rocker cover, which did improve performance for a short period of time, but the car is now back to its old ways. I am hoping that you will be able to help with this frustrating problem.