pre-detonation problem
 

i have an '89 mbz 300E that seems to have a pre-detonation problem. the car pre-detonates when the engine is warmed up and under full load only (i.e. full throttle). i have already replaced the rear crank sensor that connects to the rear of the engine to the ezl ignition control unit. i also replaced the ezl control unit, spark plugs, spark plug wires, distibutor cap & rotor, fuel distributor & EHA, resistor plug (under brake booster), air flow sensor, throttle body, and all the engine temperature sensors (on the engine head). i also use only 92 octane gas and have used various fuel treatments and octane boosters. it still pre-detonates under full throttle when the engine is warmed up.

the only thing that i can think of is carbon deposits. i have already used a carbon cleaner. it seemed to help a little, but not 100%. (the problem is still there.) i was going to use a product called sea foam carbon cleaner. does anyone have any feedback on this product?