Engine Runs Rough At Idle
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.
Turn ignition switch to ON position. Using scan tool, select INJxF PIDs from PID/DATA MONITOR & RECORD menu. There is one INJxF PID available for each engine cylinder, and the "x" indicates the appropriate injector number (1-10). AllINJxF PIDs should indicate NO (no fault). If any INJxF PID value indicates YES, an injector fault exists. Go to TEST HA: NATURAL GAS FUEL CONTROL , step 60) (Natural Gas models), or go to TEST H: FUEL CONTROL , step 56) (all others) under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.