I have a situation with knock / detonation, but ONLY when the car has been driven several miles or at highway speeds (bascially only when the engine reaches a full or hot temperature). When the motor is cold or driven for only about 10 minutes, there is no knock. And it ONLY does it when accelerating from a slower speed or when pulling away from a stop. If I hear the knock begin, I drop the pedal a little quicker and further and the knock temoparily stops. I can basically predict when the knock is going to occur.

The car:
'82 Olds Cutlass Supreme.
3.8 Liter / 231 cubic inch Buick V6 (VIN code "A")
Automatic transmission.
61,000 original miles.

I changed the plugs and wires as per factory specifications. Ran a can of BG44K in the fuel one time. The timing was advanced AND retarded and the knock was still evident, so it was returned to the specs on the label under the hood. I run the highest octane gas (91 to 93). All vacuum lines look fine.

After some research, I'm considering a new EGR. Also, I thought since it only knocks after reaching full temperature, perhaps I should put a colder thermostat in it (like a 180). The factory specs are for a 195, I have no idea what is in, but I assume it's a 195.

Any suggestions would be appreciated.

Thanks,
Chad

 

I solved the knock/detonation issue today... It was the EGR valve.