This is Harly_ Qun'* grease monkey talking. I have replaced the Idle Control Valve, and the O2 Sensor. We put in a new Throttle Position Sensor, but when it didn't fix the problem, we returned it. It doesn't seem to be a bad spark seeing as the plugs/wires are all brand new and the timing doesn't seem to be off. We took the car down to Midas for a free examination of the Cat and they say it'* fine, so no problems there (Why would they pass on our good american money?). We checked all the vacuum hoses but their just fine and the vacuum pressure is constant. Her SES light is coming on randomly and it seems more frequent after the new O2 sensor was installed.
So, long story short, the car is idling very rough and stalls out when stopped, while driving if you floor it the car seems starved for oxygen or like it'* running lean. The more gas you give it, the less power you get.
I'm not very used to working on injected cars so you'll have to be easy on the tech terms, I was raised on N/A Chevys so all this FI **** is annoying to me. It feels like I'm having to learn how to work on cars all over again.