it is possible for my dizzy to have gone bad with an external coil and msd ignition, if i have strong spark on 3 of 4 cylinders is my dizzy going out or gone bad possibly???

 

your cap maybe going, however if the icm, ckp, cmp, cyp sensors/unit fail it will throw a code, and in some cases will casue a no spark condition.

the only ways its possible for one to not spark are bad dizzy cap, rotor off balance, bad plug wires