I ask questions about cars online pretty regularly, and I always consider the responses as just ideas or guesses to look into. No matter how confident someone's online diagnosis sounds, they are guessing if they haven't looked at, touched, tested, measured, the actual car and related parts.

It sure sounds the JL did you wrong. But changing a coil and even a spark plug is pretty straight forward. I'm not sure what a zip tie would be used for - maybe holding the electrical plug to the coil? Bu ive never seen how your model of car is set up.

My guess is your problem wasn't just coils and plugs. Just a guess.