Hi all! Just picked up a Silver 2003 Nissan 350z Touring 6spd Coupe two weeks ago and after falling in love with the car it a CEL has appeared! I have put around 400 miles on the car already and it was flawless up until now. It's a p302 cylinder 2 misfire code plus an occasional pop audible from the exhaust at idle, i have to get out of the car to hear it. The car still runs fine and has power, no flashing CEL to indicate a dead misfire. I have swapped the coil pack and spark plug between cylinders 2 and 4 and after clearing the CEL it had developed a pending code on cylinder 2 once again. Both plugs looked normal. Is this more likely to be the intake plenum gasket or injector? I have put around 400 miles on the car already and it was flawless up until now.

 

Sorry if this is not posted in the right place also, I'm new here! Any feedback would be greatly appreciated.

 

You have done a good job eliminating the usual suspects (i.e., ignition packs and spark plugs).

The next most likely cause for your misfiring problem is fuel delivery: Either not enough fuel or inadequate pressure. The pressure inadequacy might be a problem with the fuel injector (and that might be a vacuum problem or a mechanical issue with the injector).

There is a test sequence for this. Google a description and you will see many solution descriptions.

 

Thank you for the responce! A bad injector was what I was thinking it was going to be as well so I swapped cylinders 2 and 4 injectors to confirm the misfire follows and replace the plenum gasket set as well while I was at it. Once i was done I did the ECU reset and throttle relearn procedures since I cleaned it all and BOOM! Purring like a kitten and no more CEL!! Must of had a very slight vacuum leak causing cylinder 2 specifically to pull in too much air and lean misfire. Absolutely love working on these cars. So happy to have a healthy VQ again!