Hey Everyone, My 2009 G37S (wife's car) has thrown this code twice now P0300 Random Misfire. I have cleared it both times with no issues. I have an appointment next week to take it in and was just wondering if anyone else has had this issue and what it was that fixed it. Just trying to get my ammo ready to through back at the dealer. any help would be greatly appreciated.

Cheers!

 

P0300 is a very generic code. More than likely, it's due to some issue with fuel or ignition issue. Tech has a flow chart to follow for trouble shooting, but first step is to replace the plugs. You don't give much details on mileage on the car, but could be plugs, coils, injectors, bad fuel. List goes on and on...

 

My P0300 turned out to be a bad downstream O2 sensor, I had replaced the left one but the other one remained there. Apparently the older sensor wasn't able to send voltage/information to the ECU as fast as the new one and thus throwing it off causing it randomise the air fuel ratio.

 

Try seafoaming it once or twice. The longer it sits the better

 

Check your air intake duct for cracks if the misfires are all on one bank. Replaced my right bank duct and no more codes. I was finding misfires on my cylinder 1, 3, and 5.

FYI: https://www.samarins.com/glossary/vacuum-leaks.html