Q: I have code P0305 on it. Ive heard it's cylinder #5 misfiring but I don't know what the issue may be.

asked by on February 12, 2017

The car is shaky and it runs alright but sometimes it dies on a stop sign or at a light. Went to the smog shop and they told me it's code P0305. The check engine light is most of the time flashing. I heard a lot of different views on this. Some say it's a bad catalytic converter some say it's just a misfire and the CEL flashing means the converter is getting harmed. I want to know what the problem is.

My car has 269000 miles.
My car has an automatic transmission.

The code P0305 is indication that cylinder number 5 is not firing all the time. When you see the check engine light flashing then the cylinder is actively misfiring. You should have the spark plug and coil checked for problems and replace the spark plug and coil as needed. Otherwise swap the number 5 and 6 cylinders coils to see if misfire moves to be a code P0306 indicating the coil is the cause of the misfire and should be replaced. If the code comes back and is still for cylinder number 5 then a compression test should be done to find the problem on cylinder 5 if any. You may just have a defective misfiring coil.

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