Additional Checks
WARNING: This page does not describe the selected car, but rather 30 other vehicles, including the 2003 Mercury Sable, 2003 Mercury Mountaineer, 2003 Mercury Marauder, 2003 Mercury Grand Marquis, and 2003 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
Ensure Powertrain Control Module (PCM) Vehicle Identification (VID) block is correct. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE under PROGRAMMING PCM in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article. Check for binding or dragging brakes. See appropriate article in BRAKES. Check engine mechanical condition. Check for incorrect PCV valve. Check intake manifold gasket, camshaft and valves and repair as necessary. See appropriate article in ENGINES. Check for contaminated Mass Airflow (MAF) sensor. Check air intake system.