Misfire at warm idle?

[sunnydays]

Sigh, back here again eh

So for background: My Z4 35is recently had a cold start misfire problem which is now fixed. The injector on bank 1 was leaking, and the valve cover was cracked. The following was changed
6x Bosch Spark Plugs
6x Eldor Coil Packs
1x Valve Cover / Gasket / Screws
3x Index 12 Rev 2 Injectors

The car now runs great, and logging a WOT run in gear 3 shows no timing corrections, and healthy fuel rail pressure. How ever when the car has been driven for a little while, and idling in warm traffic say at a set of traffic lights. I can ever so slightly hear and feel the chassis rocking as it misfires.

No codes / shadow codes are logged.

Any ideas where to start on this one guys?

Thanks!

 

[Cees Klumper]

Intake valve carbon deposits?

 

[R.E92]

It's probably spark plugs or as Cees mentioned, carbon deposits.

Did you get genuine OEM plugs? If not then did you gap them correctly?
I always had a slight shake at warm idle with the stock plugs, on my last plug change I moved to NGK 5992 plugs with a 0.22 gap and the idle is very smooth now.

 

[sunnydays]

It's probably spark plugs or as Cees mentioned, carbon deposits.

Did you get genuine OEM plugs? If not then did you gap them correctly?
I always had a slight shake at warm idle with the stock plugs, on my last plug change I moved to NGK 5992 plugs with a 0.22 gap and the idle is very smooth now.

Spark plugs are genuine OEM plugs, as mentioned all six were replaced recently. The car is currently on circa 46k miles, is it worth doing the walnut blast at this stage?

 

[R.E92]

It's probably spark plugs or as Cees mentioned, carbon deposits.

Did you get genuine OEM plugs? If not then did you gap them correctly?
I always had a slight shake at warm idle with the stock plugs, on my last plug change I moved to NGK 5992 plugs with a 0.22 gap and the idle is very smooth now.

Spark plugs are genuine OEM plugs, as mentioned all six were replaced recently. The car is currently on circa 46k miles, is it worth doing the walnut blast at this stage?

Yes, I'd do the walnut blast as a maintenance item. It probably won't fix that issue though.

If you search for unsteady idle issues on the N54 you will find topics stacked with similar reports. If no codes are logged and no lights come on then you can just ignore it. There are lots of possible causes and people have reported all kinds of things fixed the issue.

If you want to start the troubleshooting then I would start by resetting all adaptation using INPA or MHD and if that fails get a fresh set of spark plugs installed as it seems to be something most commonly brought on by spark plug changes. It's possible a plug was dropped or banged during install.

 

[sunnydays]

It's probably spark plugs or as Cees mentioned, carbon deposits.

Did you get genuine OEM plugs? If not then did you gap them correctly?
I always had a slight shake at warm idle with the stock plugs, on my last plug change I moved to NGK 5992 plugs with a 0.22 gap and the idle is very smooth now.

Spark plugs are genuine OEM plugs, as mentioned all six were replaced recently. The car is currently on circa 46k miles, is it worth doing the walnut blast at this stage?

Yes, I'd do the walnut blast as a maintenance item. It probably won't fix that issue though.

If you search for unsteady idle issues on the N54 you will find topics stacked with similar reports. If no codes are logged and no lights come on then you can just ignore it. There are lots of possible causes and people have reported all kinds of things fixed the issue.

If you want to start the troubleshooting then I would start by resetting all adaptation using INPA or MHD and if that fails get a fresh set of spark plugs installed as it seems to be something most commonly brought on by spark plug changes. It's possible a plug was dropped or banged during install.

Thanks for the confirmation R.E92. Glad to hear it is nothing to worry about, and yes have seen the many threads online chasing these issues. I will reset adaptations via MHD and see if that helps, hesitant to change the spark plugs again given they were done a few weeks ago, and non were dropped during install.

Thanks for the help!