I just installed a k&n cold air inake on my 2002 1.8L turbo beetle. Now my check engine light is constantly coming on. It is throwing code po171 (system too lean, bank 1). I installed the enclosed small air breather on the secondary air pump hose end that disconnected from the stock airbox. Is this common on the turbo beetle's or did I do something wrong? Could the maf sensor be getting too much air to adjust the fuel mixture? I think I read on a forum here about the possibility of the oil in the k&n filter mucking up the maf sensor. Anyone got any ideas? Help! The check engine light drives me crazy.