Low fuel in the fuel tank
Clogged fuel filter
Faulty Fuel Pump
Faulty Oxygen Sensor
Faulty Coolant Temperature Sensor
Faulty or dirty Mass Air Flow sensor
Engine Light ON (or Service Engine Soon Warning Light)
The Powertrain Control Module (PCM) internal circuitry can identify if the vehicle fuel system is capable of supplying adequate amounts of fuel during heavy acceleration (power enrichment). When a power enrichment mode of operation is requested during a Closed Loop operation (by heavy acceleration), the PCM provides additional fuel to the engine. Under these conditions, the PCM should detect a rich condition. Whenever this rich exhaust is not detected, a Diagnostic Trouble Code (DTC) P1171 sets. A plugged fuel filter or restricted fuel line can prevent adequate amounts of fuel from being supplied during power enrichment mode.