Intermittent backfiring with code P0300

LUCHITO63

MEMBER
2004 MAZDA 6
2.3L
4 CYL
2WD
AUTOMATIC
140,000 MILES

New battery, new ignition coil and spark plug wires, spark plugs, new alternator. Replaced valve cover gasket because oil leaking into spark plugs tube. Before all this my car was sputtering triggering P0300 but now is backfiring from the exhaust tail pipe still with p0 300. I noticed that happens when weather is more than 80 degrees outside other than that my car runs nice and smooth. To be able to continue driving I have to stop and wait for my car to cool down and drive again without problems but with the check engine light on. Any ideas please let me know. Appreciate your advice. Thanks. Luis.

Tuesday, September 24th, 2019 AT 3:06 AM

1 Reply

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

Direct Trouble Code (DTC) P0300 is the DTC for a random misfire with your engine. The fact that you are having an exhaust backfire would lead towards an ignition issue, as it suggests that not of the air:fuel mixture is getting burnt in your engine's combustion chambers. There could be numerous reasons why this DTC is rearing it's ugly head, so in the diagrams down below I have included the vehicle manufacturers diagnostic troubleshooting guide for DTC P0300. You will need a code reader with the availability to get and read freeze frame data as well as PIDS though. Please go through this guide and get back to us with what you find out.

Thanks,
Alex
2CarPros

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