What the Heck
 

I was out running the truck up and checking the timing and when I had the timing light on it wasnt continuously flashing it would do it for a sec or so then start flashing every so much. Could it be because the ignition isnt firing right or is it the light?

Re: What the Heck
 

More than likely the light is having a problem. Could also be the number one spark plug wire. Put it on another wire to rule the wire out and go from there.