all started when I was driving and it was running great and all of a sudden the engine light comes on and it starts running like its firing on 3 cylinders, then when the light would cut off it would go back to running great, so I change all the plugs and wires and still the same result.So I start pulling plugs off while it's running and the engine light is on and missing etc. and realize that one tower off each ignition coil block isn't firing,#1 off first block and #4 off the second block which fire in a pair and is for the exhaust , well what I find weird is that it comes and goes it starts firing again once the engine light goes out but not both only#1, but #4 always stays dead, but when #1 does decide to start firing it actually runs okay and the engine light cuts off, but it's getting worse and worse and what I need to know is if it's the ICM or the ignition coils , I just think it would be strange for one tower off each to go bad but idk help please!!?