Sounds like a coil issue. You sound like you have a little skill in working on the car. So that'* a good start. here is a write up on testing the coils.
Another thing you can try is take a spray bottle with water and mist the coils, wires, and plugs while the engine is running. Then turn off all the lights so it'* real dark. Watch for blue flashing. If you see that, you have a ground short. Make note of where you see it and let use know.