Some 2004-06 Mitsubishi Lancer models with 2.0-liter engines may run rough and illuminate the check engine light. When you hook up your scan tool, you may find trouble code P0171 (lean exhaust) stored in the PCM.
According to Mitsubishi, one likely cause for the code is a vacuum leak between the fuel injector insulators and the intake manifold ports. Installing four new-design insulators and injector O-rings (part No. MD087060 and part No. 1465A188, respectively) should eliminate the vacuum leak. After reinstalling the injectors, make sure that the top of the insulators are flush with the injectors and that the bottom is flush with the intake manifold ports. If you notice gaps, press down firmly on the fuel rail until they're eliminated.
"Factory Fixes" is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at [email protected].