#1 cylinder ignites fuel sporadically. No vacuum leaks that I could find, new Pertronix. There is firng at #1 cylinder,however with engine warm and idling , you can disconnect #1 plug wire and their is no change in the idle. The engine runs strong under acceleration but when held to constant rpm, it tends to rock the car back and forth a little , I'm thinking it's igniting the fuel sporadically. It does this at all rpms , just more noticeable at lower speeds. What do yall think the problem might be? Also, new spark plugs ,ignition parts new, carbs check ok, verified the spordic flaming with the colourtune system. All the other cylinders igniting correctly.