Ford P1091 OBD-II Trouble Code Definition:
P1091 Pre-Catalyst Fuel Trim Too Rich Bank 1
P1091 Ford OBD-II Trouble CodeDescription:
Causes
– Low fuel pressure
– Large vacuum leak on engine
– Faulty Mass Air Flow (MAF) sensor
– Faulty Ignition
– Faulty fuel injector
– Large vacuum leak on engine
– Faulty Mass Air Flow (MAF) sensor
– Faulty Ignition
– Faulty fuel injector
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)