I installed a HEI kit on my v6 from CRT performance a few years ago. It would intermittently fail to start due to lack of spark, but I was always able to cure it by just tapping the top of the distributor cap with a screwdriver. It got worse and worse, so I finally replaced the coil, brush, and rotor 2 weeks ago and thought I had fixed it. However, the problem is back and the tapping solution works again. At first I thought it was an accidental anti-theft device, but now it really annoys me. Any thoughts?