In-gear idle issues

Also the Blaster 2 coil does not need a ballast resistor. Ballast was for OE style coils and to prevent burning points, neither of which you have. You might want to try bypassing the ballast resistor to see if giving the coil the full 12v will help your issue.
Maybe, maybe not. It depends on which part number he has. They do make Blaster coils that require a ballast.