My P15 has a cold start miss. Engine starts right up but misses, then on acceleration it smokes. I assume the smoke is because it is loading up from the miss. Smoke is sort of gray in color. After the car goes about a block or two, the miss goes away and so does the smoke. My heat riser isn't working, but I can open and close it with a pliers, makes no difference in the miss, open or closed. I rebuilt my carb, have an electric fuel pump with a pressure regulator set at 4lbs. I am running Autolite 306 plugs and synthetic blend motor oil. Runs great after a couple of blocks. Compression on all cylinders is in range but low 85-90. I am also running 12 volts electrical & ignition. I have also removed plug wires one at a time when cold but can't pin point miss to any one cylinder. Any ideas on this?