I finally brought the brick in for service after giving up on diagnosing the emissions problem. Turns out I had a bad air mass meter and I had it replaced. I thought the diagnostics box was broken but it turns out that it just needed to be reset with a bunch of button holds and clicks. D-oh! Would have been good to know that before.
Once fixed the car doesn’t lag, gets good mileage and passed NJ inspection. I took the opportunity this weekend to replace the plugs, cap and rotor. Above are the old plugs. They didn’t look too bad after 36k miles.