I bought the car for a dealership from out of state, and wrestled with the sales guy a bit about the service interval performed along with the CPO. I can look at my paperwork, but I'm pretty sure they did the 4 year. I do remember that the plugs were part of it.

I like the idea of following up on the coils. I need to take it in again for a whistling passenger mirror and I'll bring the coils up then. I think I'll have a hard time with it if I don't have any more issues, but we'll see. I also have an independent that I can check with...

Thanks for all the advice and comments!