I have a 1994 Volvo Turbo with 120K miles. Everytime I start driving the car when cold, it has pinging and knocking anytime it goes above 2000 RPM - worse at 2500. After the car warms up the pinging sound almost disappears. I recently replaced the spark plugs, cap, rotor, wires, distributor, fuel filter but this problem still has not gone away.

When I first got the car the dealership - the check engine light was on because of a knock sensor. However, after the code was reset, this code never came up again (almost a year).

I always use super gasoline, so it can't be the fuel.

Any ideas - I don't want to damage my engine? Thank you!