Multiple random misfires on all cylinders

[Lgc7906]

Hey guys


I searched the forum for anybody with similar issues but have come to a roadblock.

My baby 2011 camaro RS V6 has been having issues and no dealership or mechanic seems to want to find the issue let alone fix it. They tell me its fine and drive.

So I had p0420/p0430 codes popping up regularly due to misfires happening years ago. Finally got to replacing them. That fixed that issue but just before replacing them the car would misfire on cylinder 5 but not store the code (CEL would turn off by its self after driving for 10/15 min).

This misfire happened once and then the other day it started misfiring on the highway but randomly at intervals of 15/20 min. The code was stored this time.

I replaced coil packs and sparkplugs on all cylinders, then when I drove it the other day it started misfiring on cylinder 1,2,3 and 5. And then stalled right there on the road.

Restarting the car the misfires dissappeared. Drove home no problems. Turned her off came back 10 min later restarted it. Started misfiring on all 6 cylinders while idling. Turned her off and back on. And all the misfires stopped. Permanent stored codes for misfire on cylinder 1,2,3 and 5.

No other work was done to the car other than new cats, sparkplugs and coilpacks. Oil has always meticulously been changed between 4500-5000 km and topped up when low.

Which reminds me of another case of concern which nobody seems to want to address.

When pulling the cylinder 6 sparkplug the sparkplug was oily (especially the white ceramic part) there was a decent amount of oil on just that sparkplug. The other sparkplugs had some soot on the tips but looked fine.

If anybody has any clue what this could be any help and advice is appreciated.

Thanks guys, really don't want to get rid of her as like most people here love their camaro.


No mods no upgrades done to it. And about 202kms on it. Timing chain hasn't heen replaced as far as I know but that would throw a code no?

[KillboyPowerhead]

Just an newbie/inexperienced guess: I'd get the timing chain looked at to see if it's loose (could do it yourself relatively easily, just need to remove the intake manifold and whatnot and pop off one of the valve covers). Perhaps it's tight enough when cold, and as it warms up it stretches just enough to start throwing codes. 202k on these timing chains, I wouldn't be surprised if it needs to be replaced.

[NOT A 45]

Originally Posted by Lgc7906

Hey guys


I searched the forum for anybody with similar issues but have come to a roadblock.

My baby 2011 camaro RS V6 has been having issues and no dealership or mechanic seems to want to find the issue let alone fix it. They tell me its fine and drive.

So I had p0420/p0430 codes popping up regularly due to misfires happening years ago. Finally got to replacing them. That fixed that issue but just before replacing them the car would misfire on cylinder 5 but not store the code (CEL would turn off by its self after driving for 10/15 min).

This misfire happened once and then the other day it started misfiring on the highway but randomly at intervals of 15/20 min. The code was stored this time.

I replaced coil packs and sparkplugs on all cylinders, then when I drove it the other day it started misfiring on cylinder 1,2,3 and 5. And then stalled right there on the road.

Restarting the car the misfires dissappeared. Drove home no problems. Turned her off came back 10 min later restarted it. Started misfiring on all 6 cylinders while idling. Turned her off and back on. And all the misfires stopped. Permanent stored codes for misfire on cylinder 1,2,3 and 5.

No other work was done to the car other than new cats, sparkplugs and coilpacks. Oil has always meticulously been changed between 4500-5000 km and topped up when low.

Which reminds me of another case of concern which nobody seems to want to address.

When pulling the cylinder 6 sparkplug the sparkplug was oily (especially the white ceramic part) there was a decent amount of oil on just that sparkplug. The other sparkplugs had some soot on the tips but looked fine.

If anybody has any clue what this could be any help and advice is appreciated.

Thanks guys, really don't want to get rid of her as like most people here love their camaro.


No mods no upgrades done to it. And about 202kms on it. Timing chain hasn't heen replaced as far as I know but that would throw a code no?

The early 3.6 were very prone to carbon build up. Eventually it causes multiple random cylinder misfires. Take it to your dealer and have them perform a de carbon procedure. The chemical we use works very well.

[xstuntman]

Those codes are for the cats.
Modded exhaust, bad cats, or ?

[NOT A 45]

Originally Posted by xstuntman

Those codes are for the cats.
Modded exhaust, bad cats, or ?

Pretty sure his codes are related to the misfires. Misfires quickly degrade the catalyst. I wouldn't address those codes until the misfire condition is fixed or it will ruin the new cats in short order.

[Pkeen]

I don't know if this is the problem, but I know they had issues with the reluctor wheel moving on the crank. I think its an easy fix ,I've read you can bump it back to its proper location and have it spot welded so it doesn't move again.

[Pkeen]

Lgc7906, did you figure out the problem yet ?