while driving, the tach will fluctuate badly (jump between 2-6k) and my engine stumbles alot while this is happening. i did some testing the best i could. with ignition off. i connect my noid light to a ground and probe the positive of my coil and i get a light. i connect my noid light to the battery positive. and probe the coil ground and get a light, but as soon as i turn my ignition to the on position. the light goes off. I think this has something to do with why my engine will not start anymore and just cranks. I am not sure where to go with it from here.

 

Put away your 'noid light, and get out your meter. What's the actual voltage measurement at the coil?

 

11.7 or so.