Misfire at idle
Thread Starter
|
Registered User
Joined: Oct 2017
Posts: 10
Likes: 0
Misfire at idle
So my car has been having misfires at idle for months now. It started with a cery aggressive misfire like 3 every second, so I replaced the spark plug and the plug was soaked in oil and it got all over the ignition coil. It sends a P0306 code. Recently its been getting worse and one day when i was driving the check engine light started flashing and the car felt like it was going to barely make it home. It has gotten better since then but the misfire is still present at idle. When I step on the gas there is a big hesitation with acceleration. I have tried pretty much everything. Ive replaced both valve covers and valve cover gaskets, ive replaced the spark plugs and the 6th cylinder's ignition coil, ive replaced the intake manifold gaskets, ive replaved the PCV valve. Ive tried cleaning the throttle body with seafoam. I tried resetting the ECU and relearning the idle. I was considering either taking it to the dealer and having a diagnostic ran or going for a cam positioning sensor. Please if anyone has any clue what could be causing the misfire let me know.
You can listen to the injectors and make sure they all sound the same. I haven't done this on my G so don't know how accessible they are with the intake tube in place. With a mechanics stethoscope (or a long screwdriver with the handle in your ear) firmly touching the injectors, you can hear the ticking sound they make when they actuate. If any one of them sounds significantly different like you don't hear ticking for instance, you could have a problem with the injector or the harness to it and this can cause a misfire just like a bad coil or plug. I had one act up on me in a different vehicle and was able to "fix" it by tapping the injector and it started ticking again and the misfire that made the car completely undriveable disappeared immediately.
It may not be your problem but doesn't hurt to try and you'll learn another easy thing to check when troubleshooting misfires. Search youtube if you don't understand what I'm saying about using a screwdriver to do this.
It may not be your problem but doesn't hurt to try and you'll learn another easy thing to check when troubleshooting misfires. Search youtube if you don't understand what I'm saying about using a screwdriver to do this.
Thread Starter
|
Registered User
Joined: Oct 2017
Posts: 10
Likes: 0
You can listen to the injectors and make sure they all sound the same. I haven't done this on my G so don't know how accessible they are with the intake tube in place. With a mechanics stethoscope (or a long screwdriver with the handle in your ear) firmly touching the injectors, you can hear the ticking sound they make when they actuate. If any one of them sounds significantly different like you don't hear ticking for instance, you could have a problem with the injector or the harness to it and this can cause a misfire just like a bad coil or plug. I had one act up on me in a different vehicle and was able to "fix" it by tapping the injector and it started ticking again and the misfire that made the car completely undriveable disappeared immediately.
It may not be your problem but doesn't hurt to try and you'll learn another easy thing to check when troubleshooting misfires. Search youtube if you don't understand what I'm saying about using a screwdriver to do this.
It may not be your problem but doesn't hurt to try and you'll learn another easy thing to check when troubleshooting misfires. Search youtube if you don't understand what I'm saying about using a screwdriver to do this.
BANNED!!!
Joined: May 2017
Posts: 14,837
Likes: 2,497
From: Washington State
Coupe 6MT Premium RAS
Well then there's the problem, pull the plug again and visually inspect it, swap coil packs with another cylinder and see if the misfire moves to that cylinder, stethoscope the injector, if it's still misfiring compression test that cylinder.
Thread
Thread Starter
Forum
Replies
Last Post
cfauvel
Engine, Drivetrain & Forced-Induction
13
Oct 31, 2016 09:14 AM
Genthusiast35
G35 Coupe V35 2003 - 07
26
Feb 12, 2016 12:22 PM
Schuma3955
G35 Sedan V36 2007- 08
18
Jan 26, 2012 06:03 PM
