Car is running really rough with code p0300 multiple cylinder misfire.. 2003 Chrysler sebring 3.0 just rebuilt engine...

Marvin

• 85242 Answers
• Posted on Jul 30, 2008

SOURCE: diagnostic codes for 200 Daewoo Lanos..........

Do you feel a misfire?? Random misfires are usually caused by a lean fuel mixture, the reasons that cause this a to many to list here.

SOURCE: engine misfires

You didnt mention having changed the spark plug wires, so that is another item that could be culprit as well. As well, it could be a coil pack that is not working properly.

I cannot recall at the moment if that model year uses coil on plugs or if it uses coil packs. Either way, if it uses a coil on plug set up, take the one for the #3 cylinder and move it to say #4 or anyone of your choice and see if the misfire follows

If it uses coil packs, there is likely one coil pack that controls two cylinders. In that case just swap the coil pack with an adjacent one and see if the problem follows. Pay attention to where the spark plug wires go because it will be an issue if you get them mixed up. You just swap the coil packs around.

I would, however, start with the spark plug wires if you have not changed them already.

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?

Ronny Bennett Sr.

• 6988 Answers
• Posted on Nov 11, 2009

SOURCE: 2003 kia # 3 misfire/ runs rough

Replace the coil for number 3 cylinder.

SOURCE: get multiple misfire codes. P0300 - P0303. If this

This could be a coil problem but i would start by changeing the plug wires and checking each plug.