Hey everyone I own a 2004 G35 Coupe 6MT with around 130k miles on it. has a plenum spacer, cold air intake, and is tuned. Owned the car for almost 3 years and am the 3rd owner. drove great for 2 years and then for the last year its been on and off misfire. When it does misfire it sounds like a diesel truck and has a noticeable loss of power. Can also smell some gas. I got curious and decided to hit 2 step in hopes that it would clear it up and to my surprise, it did! Back to normal, or so I thought smh. After a couple drives the misfire came back so i would try the 2 step again (popping the exhaust) and that kept working until sometimes it wouldnt. so based off those symptoms im thinking its gotta be fuel related either fuel injectors are clogged or a bad coil pack(s). installed all brand new NGK spark plugs less than 6 months ago. Recently i got a new battery for the car and immediately the car started to drive better and the misfire was gone, but now it is back again and wont go away.

Yes the SES light is on and sometimes blinks and sometimes stays light with no blink. when the misfire goes away the SES light goes away and the car drives amazing.

When i scanned the code it would never give me the same code twice in a row and sometimes it would say there was no code even tho it was on the car. the codes it gave were Camshaft Position Sensor or Valve Cover Gasket.

Any suggestions are greatly appreciated as i love this car and due to my current situation this is my only car and have to drive it for work which is luckily only 10 minutes away. Thank you all!

 

You check for a ground wire?? I got the same issue so im on the hunt for new coils new battery and plugs, going to check all grounds as well. And do the big 3 upgrade while I'm under the car..

 

Start writing the code numbers down and post them here.

If it threw a cam sensor code then you probably need new cam sensors. I would replace them both (2004 only has two sensors, one straight, one angled). Be sure to only use Hitachi or Genuine OEM Nissan sensors (Hitachi was the OEM manufacturer for that part).

These cars do NOT play nice with aftermarket sensors.

 

Turns out cylinder #3 wasn't firing so I swapped the coil pack out with a hitachi oem one and the car is running great again. Hope you find out what causing yours and is an easy fix!

 

Yea I forgot to put the code in the post 😅 but it was P0303 so I replaced that coil pack with a new OEM one and it fixed my issue

 

Ahh yeah, P0303 is cylinder 3 misfire. Glad you got it all sorted out.