I've searched and read but have run out of plans, please help.

My 95 525iM (M50 with vanos, South Africa so no cat, O2 sensor or charcoal canister) has a very irritating lack of power, generally feels lazy. Don't want to go into too much detail but have done a number of things to try and eliminate the problem (new filters, checked fuel pump delivery pressure, reset computer, gave it 2 cans of combustion chamber cleaner, new plugs).

Eventually paid someone to read error codes (as stomp test does not work on RSA cars) and got the following: Fuel tank ventilation valve, Knock (Ping) sensor.

Checked fuel tank ventilation, no build up of pressure, and also checked fuel pump delivery pressure, I am thus happy that there is no problem with fuel supply.

So my question is can a ping sensor be faulty and the car is not be pinging, and if it is faulty can it hamper performance?

Any thoughts!