Insufficient Fueling
WARNING: This page does not describe the selected car, but rather 16 other vehicles, including the 2011 Mercury Mariner, 2011 Lincoln Navigator L, 2011 Lincoln Navigator, 2011 Lincoln MKX, and 2011 Lincoln MKT. However, it is still accessible from the selected car via links, so may be relevant.
With this condition, the engine runs lean of stoichiometry (14.7:1 air/fuel ratio) if the PCM is not able to compensate enough to correct for the condition. This condition is caused by a fuel delivery system concern that restricts or limits the amount of fuel being delivered to the engine. This condition is normally apparent as the engine is under a heavy load and at high RPM, when a higher volume of fuel is required. If the freeze frame data indicates the concern occurs under a heavy load and at higher RPM, a check of the fuel delivery system (checking fuel pressure with engine under a load) is the best starting point. Examples of this include:
- low fuel pressure (fuel pump, fuel filter, fuel leaks, restricted fuel supply lines)
- fuel injector concerns