I would say since you've replaced the plugs already to test the ign. coils. You can swap them around but you have 3 that sound like they might be gone. So swap side to side and see. Another way is, with the car running, gently lift the coil off the spark plug and listen for arcing, if there isn't any, then that coil isn't working. If you were closer I could have lent a hand.
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