My buddy has a 1997 bird with a 3.8. He was getting a rough idle, so he swapped out the old plugs and wires. He's still getting a misfire on 1 & 5. Plugs got spark and compression in the cylinder. Thought it could be the coil pack but from what ive read, chances of it being a coil pack is slim to none; any idea as to what could cause the misfire? Could it be a ECM issue? Bad wire/plug? Any information to check for the issue would be greatly appreciated!