Ok so I took my car in for the fourth time this past monday because of random misfire codes causing a steady check engine light, and the occasional flashing check engine on the highway. Fourth time right? Ford is requiring that I replace the complete original airbox going all the way back to the wheel well before they can continue further warranty coverage. (2005 Duratec Zx4, Steeda CAI, pulleys, and TruBendz cat-back) I replaced all of the parts to the airbox that I had but apparently the air filter is way back underneath in the original system and I did not have that part anymore. The dealer service place is requiring me to pay $411.00 before tax to get the rest of the original air system parts and time included. I think this is bullshit. If someone out there has any clues how I can go about getting this fixed without paying $420 please let me know. I have seen the warranty coverage website about aftermarket modifications on new vehicles, and so far the plan is to go to the dealer tomorrow with that and see what happens. I SERIOUSLY doubt that it's an airflow problem that would be causing random misfires, yet they will not proceed unless I replace the stock airbox. Someone PLEASE let me know your ideas.