Engine light came on and mercedes c180 manual transmission became more"heavy" on road, needs more acceleration and fuel consumption increased badly

Electrician says knock sensor have to be replaced. When diagnosed it listed two problems. Mass air flow sensor and knock sensor had electrical fault. Mass air flow sensor was very dirty and had to be cleaned.
Did the mass air flow sensor cause the knock sensor fault? If the MAF sensor is only cleaned will it clear off the knock sensor fault? Do the MAF sensors (2) have to be replaced?
Kindly advise