Lean fuel conditions

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! A P0171 lean code on your Mazdaspeed Protege can be like chasing a ghost! Since you've already cleaned the MAF sensor and checked for vacuum leaks, you're on the right track. However, with that cold air intake installed, it might be messing with the MAF readings, causing the ECU to think you're running lean. Double-check that the intake’s properly sealed, and consider if the air filter is too restrictive or dirty. Also, look into fuel delivery issues, like a weak fuel pump or clogged injectors. Those RPM dips on start-up could be a clue. If you need any further advice or want help finding a trusted RepairPal shop in your area, please feel free to call us at 877-913-1554!