Originally Posted by M3PO
Just a bit of anecdotal evidence but Tom immediately suggested this as the "problem" and said he had seen this before. In fact, he showed me the plots for a car that made 308 WHP (stock) with old plugs and software. It was misfiring and had failed smog (not codes though). The updated software made a huge difference (I wanna say it made 345 after updating the software but don't quote me on that).
Was your car CPOed? I'm curious. I would think CPO cars would have everything up to date.