I am getting an inconsistent spark from my coil. I replaced the coil last year with an aftermark MSD coil. I also did the timing bump. I can some times start my 1995 F150 and drive it and it does fine and other times it will not start and if it does it will not run properly.

All of the plugs, wires, distributor cap and rotor are new.

 

It would help to know what engine, trans, induction system, miles, maintenance, mods, damage, & repairs the truck has. I highly recommend creating a signature so that info appears with each of your posts. You can omit "19__ F150" since those are assumed. Read these captions:

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I also recommend 10°BTDC timing for all EFIs.