Timming

[RED1985]

I'm been lurking on the site for a few months and just recently signed up. I have a 1985 Chevy C10 Stepside with a 350 crate motor from the previose owner. The truck was running ruff so I checked the timing and it was at about 16 degrees. I adjusted it to 4 degrees and it ran very well. This was three weeks ago. Yesterday I went to take the truck out and it was running very ruff, almost like a misfire. I went to check the timming and it flashes a few times and goes blank and then will start back flashing again. I borrowed a friends light and get the same thing. Does anyone know what would cause this? I'm going to head out and get a plug wire tool so that I can pull each wire while it running to see if I have one missing.

I search the forums and could not find anything like this.