This was my very first thought and test. I've checked every hose and other possible leak points and have not found a leak yet. I'm aware this could still be a possibility.Its a lot easier to work on CCC systems with either a analog dwell meter or a old OBD1 scanner. If its just spark knock you likely have a vacuum leak leaning out the fuel mixture. Disconnecting the M/C solenoid causes the fuel mixture to go full rich which can offset a vacuum leak. The off position for the M/C solenoid is rich, the on position is lean. Finding the vacuum leak is the hard part.
Does anyone have a "can't believe I finally found the vacuum leak at the ____" story...?
I have a dwell meter. What would I look for? What would that reading tell me is or isn't the problem?