Loss of acceleration power?

I bought the car at an auction about 3 months ago. It first had a problem switching off while driving, took it to a mechanic and he said it was the gasket. We fixed that and a week later it lost power while accelerating on the highway, I then took it back to the mechanic and now the problem was one of the ignition coils, which was replaced and a week later we are back to the same problem. Do you by any chance know who I can resolve this, and do you recommend a full major service as a fix for my problem?