so my 2008 350z has a misfire all the time during cold starts only , I’ve changed the sparks plugs and coil packs but misfire is still there , I took it to a shop and they didn’t find any vacuum leaks so at this point I’m not so sure what it could be. The only other time it misfires is when I hold the rpms anywhere between 1k-2k rpms once it’s over 2k rpms there’s no misfire. Car does idle a bit over 1k in neutral. The other 2 codes (p0011 and p0021) I’ve read it’s usually because of the gallery gaskets but my cars oil pressure seems right , not too low or not too high. Car has 40,xxx miles. Any suggestions of what it can be ? Any help is appreciated.

 

for the P0300 that is annoying because it doesn't tell you which cylinder....and it may be related to something completely different elsewhere. Maybe someone will chime in on that point, but seeing that you've replaced plugs and coils, the only thing left is injectors.

Fast idle:
There is a Idle Relearn Procedure that is found in the mech manuals....if you search youtube you'll find it there too...simple....that should get your idle rpm down. Before you do that re-learn procedure , clean the the butterfly of the Throttle Body (don't disconnect the cable though).
Update: read somewhere else on here to NOT clean the the throttle body whilst STILL connected. I actually did clean mine and my wife's G35's TB like I stated with no problems, but....


The p0011 and p0021, point to the VVT solenoids, but not necessarily that they are bad (there is no sensor on them...the code is thrown from the camshaft sensor)
there are many threads here that state to first
1 - remove them , clean them to make sure there is no blockage and test them via a 12v source to make sure they work.
2 - do a full oil-change

Then after clearing the code and it comes back ...replace the camshaft sensors with OEM hitachi sensors.....I personally had a camshaft sensor go bad...replaced with Intermotor, and the car acted fine, but the code kept coming back....replaced a second time with OEM and the code hasn't come back.

 

What brand and model of spark plugs did you swap to?

 

appreciate it ! will look into that , I've been trying to solve this issue for a while but cant seem to find the problem.

 

I used ngk

 

[QUOTE=CFAUVEL;11009089]for the P0300 that is annoying because it doesn't tell you which cylinder....and it may be related to something completely different elsewhere. Maybe someone will chime in on that point, but seeing that you've replaced plugs and coils, the only thing left is injectors.

Fast idle:
There is a Idle Relearn Procedure that is found in the mech manuals....if you search youtube you'll find it there too...simple....that should get your idle rpm down. Before you do that re-learn procedure , clean the the butterfly of the Throttle Body (don't disconnect the cable though).
Update: read somewhere else on here to NOT clean the the throttle body whilst STILL connected. I actually did clean mine and my wife's G35's TB like I stated with no problems, but....


The p0011 and p0021, point to the VVT solenoids, but not necessarily that they are bad (there is no sensor on them...the code is thrown from the camshaft sensor)
there are many threads here that state to first
1 - remove them , clean them to make sure there is no blockage and test them via a 12v source to make sure they work.
2 - do a full oil-change

Then after clearing the code and it comes back ...replace the camshaft sensors with OEM hitachi sensors.....I personally had a camshaft sensor go bad...replaced with Intermotor, and the car acted fine, but the code kept coming back....replaced a second time with OEM and the code hasn't come back.[/QUOTE




appreciate it ! will look into that , I've been trying to solve this issue for a while but cant seem to find the problem.