Q: Where is the fuel filter on. A mercury milan 2009

Hello, thank you for writing in. The fuel filter is located b,etween the fuel tank and the engine. With that being said, the filter will be on the same side of the vehicle as the gas tank, usually right behind one of the front wheels. If you look under the vehicle, you will see the fuel lines running along the frame or body of the car. Along those lines will be a metal cylinder about the size of your fist. Considering your symptoms, if replacing the filter does not completely resolve the issue, you will want to consider using a fuel injector cleaner, and looking into your fuel pump. Fuel injector cleaner will make the debris your cleaning out be burned up in the engine, so expect to see that as heavy exhaust or feel it while driving. For more help diagnosing the symptoms, contact our service department to schedule an appointment.