I have 2008 C70 automatic 2.4 , "Sometimes" when i am driving , suddenly i can't increase acceleration and my engine rpm and speed decreasing to be zero and after stoping car , my car shuting down. After 1 minute i restart car and then it working well again.
For example when i was driving in the high way on 100 km/h speed, and i was pressing gas pedal continiusly, suddenly i saw that car not accelerating anymore and my speed and engine rpm decreasing like i am not pressing gas pedal.

 

I would ensure battery was 100% and reset ECM module.

 

thanks for reply, i changed my battery 1 week ago and they did everything for me , what is ECT reset? do i need to do it? but it happen when i drive not on starting car.