Causes cylinder misfire

Romel Edmondson

• 68 Answers
• Posted on Feb 14, 2009

SOURCE: 2000 CIVIC System too lean Cylinder 3 and 4 misfire Deteced

1. P0171: This means that the oxygen sensor has detected a lean air-fuel ratio. This can be caused due to a vaccuum leak or a problem in the HO2S circuit or the HO2S (Heated Oxygen Sensor) itself. (Bank one Sensor one). This is commonly located along the exhaust pipe. It could also be a bad Mass Air Flow sensor or a bad Engine Coolant Temperature sensor. Diagnostic checks will be needed to be carried out to be verified though
2. Well as for the other codes, it means #3&4 cylinders are misfiring. It is a possibility that the P0171 code mite have caused the others to show up. I can be wrong though. But it is a strong possibility. If the air fuel mixtue is too lean indeed, mis-firing will occur, unless it is an actual electronic and not a mechnical problem. By the way, when these codes appear, how is the engine's performance. Does it remain the same or behaves poorly?

SOURCE: 99 cougar v6 P0352 misfire cylinder 3 and 4 replaced igntn coil..

Had the same problem, car was misfiring on cylinder 3 and 4. replaced wires, plugs, and ignition coil. still misfired on the same cynlinders. turned out the main engine wiring harness plug in was coming loose. spent well over $150 on the unneccesary repairs and ultimately fixed the problem wit a $3 bag of wire ties to hold the plug in...

SOURCE: p0304 cylinder 4 misfire

2001 oldsmobile silhouette van misfire on cylinder 4