Is the sensor gapped correctly also check for any metal swarf on the end it will make it behave erratically normally it should be providing a clean pulse is it a powered sensor or magnetic .
What is your start timing at 12 or 10 + 12 = 22
It is gapped correctly, will check to see if anything is on it. Its a powered sensor. Still figuring this all out, just see the advance on cranking, where do I find the base timing?