go to home depot and get an impact driver for $20. that should do the trick. if you pull off the distributor, make sure you mark exactly how it was positioned so that you can line it back up when you re-install. for me, it was easier to pull the distributor and use an impact wrench to crack that screw. i just used a sharpie to draw a line where the distributor mounts so i knew exactly what position it was in, so as not to throw off the timing.

now that i think about it, it's more likely the igniter than the coil, because the coil would either work or not. the igniter on the other hand, could be fritzy, causing an intermittent problem.