Why does my P0300 misfire in cylinders 1-3?

Why does my P0300 misfire in cylinders 1-3?

UPDATE: after clearing the code back in April, the CEL did not reappear. There has always been an intermittent slightly rough idle though. Well, today it happened again. Loss of power, rough idle, and flashing CEL. I pulled a P0132 02 sensor high circuit as well as the same P300 with high misfires in cylinders 1, 3, and 5.

What to do if your P0300 misfire on Bank 2?

If you suspect a cat issue, you can attempt to remove the upstream O2 on that bank and see if the engine runs any better. You could also install a backpressure gauge, if you have one available. FYI, the O2 test isn’t foolproof. If the cat is plugged solid, even removing the O2 may not allow enough flow to create a noticeable difference.

What does the code P0300 stand for?

Code P0300 stands for “Random or Multiple Cylinder Misfire Detected.” This diagnostic trouble code (DTC) indicates that your car’s computer has detected an engine misfire that’s random and/or appearing on multiple cylinders.

Are there any misfires in 1-3-5 cylinders?

Today while in gear and at a stop light (foot on brake) engine was shaking pretty good and the check engine light was flashing and beeping (according to the wife). I scanned the code and pulled a P0300. Misfire check showed heavy misfires in cylinders 1-3-5. Any ideas?

UPDATE: after clearing the code back in April, the CEL did not reappear. There has always been an intermittent slightly rough idle though. Well, today it happened again. Loss of power, rough idle, and flashing CEL. I pulled a P0132 02 sensor high circuit as well as the same P300 with high misfires in cylinders 1, 3, and 5.

If you suspect a cat issue, you can attempt to remove the upstream O2 on that bank and see if the engine runs any better. You could also install a backpressure gauge, if you have one available. FYI, the O2 test isn’t foolproof. If the cat is plugged solid, even removing the O2 may not allow enough flow to create a noticeable difference.

Code P0300 stands for “Random or Multiple Cylinder Misfire Detected.” This diagnostic trouble code (DTC) indicates that your car’s computer has detected an engine misfire that’s random and/or appearing on multiple cylinders.

Can a bad O2 sensor cause a P0300 code?

If the catalytic converter becomes restricted, it can create enough back pressure to cause a misfire and trigger code P0300. Can a bad O2 sensor cause a P0300 code?