Hi to all members, i have a 2005 c200 kompressor 61 000 km (38k miles) and check engine light came on. 1-st i change the MAS sensor and the light goes off but after some miles it came again on. So i change the fuel filter oil etc... but no result. The car is shaking a little bit on idle when the a/c is not switched on. Before the change of fuel filter on neutral the revs are going alone between 700 and 1300-1400 and down again , the car is building revs alone. I don't know what to do, so please give me advise.

Thanks in advance