Engine rumbles and stumbles in lower RPM

Hi Folks,

a few days ago I recognized, that my M3 would hesitate in 3rd gear and sputter slightly.

After an extensive Autobahn & backroad chase on Saturday, the rumbling and stumbling became very apparent between 2000-3000 revs.
A kind of misfire at cold & warm start joined the chorus. No warning lights or else. Filled up with 102 ROZ fuel during the night and returned back home.

I checked the codes yesterday and it gave me P0308 - misfire on cyl. 8.

Will now proceed to have the spark-plugs changed and coil pack checked.

Any other recommendations? Any good tutorials / DIYs for changing the spark plugs and coils (including torque specs etc.?)?

M3 is a 2008 with now roughly 93k kilometers on the clock (57k mls).

Give me some confidence - should be the spark/coil only, right?

Cheers,
Seb

The searcher will find - try the DYI section and you'll find what you need to change plugs for sure.

Thanks Helmsman - too nervous.

The Tutorial for the spark-plugs here in the DIY section was indeed very helpful already.

I will have a specialist look at it on Saturday as well, will let you all know the outcome. An inspection would be due soon, so we gonna prepone the same, fix the leaking diff, change the DCT transmission oil. Might even be the spark-plug(s) only, not really sure, when they were last changed.

Consider Idle control valve if the plug change doesnt solve this. Check for codes.

Thanks Mvy - will have to deep dive into diagnostics, but regular code reader just came back with P0308.

First car with such a sophisticated engine, I'm for sure overreacting with all my nervousness

DerEisbaer wrote

Thanks Mvy - will have to deep dive into diagnostics, but regular code reader just came back with P0308.

First car with such a sophisticated engine, I'm for sure overreacting with all my nervousness

Try this code list out mate. P0308 is suggested to be misfire on cyl 8.
http://wiki.rcollins.org/core/index.php/ECU_Error_Codes:BMW_Engine_(S65),_ECU_(MSS-60)

Helmsman wrote

Try this code list out mate. P0308 is suggested to be misfire on cyl 8.
http://wiki.rcollins.org/core/index.php/ECU_Error_Codes:BMW_Engine_(S65),_ECU_(MSS-60)

Thanks.

Had found the full list of codes already, and torque gave me the same feedback - misfire on cylinder 8.

Dropped the car at the shop on Saturday. First tests will be coil pack and spark plugs. Could have done the work at home as well, however the DCT is slighlty leaking and so is the diff, the service is due shortly and hence I decided to just get it all done. Will keep you posted.

DerEisbaer wrote

Thanks.

Had found the full list of codes already, and torque gave me the same feedback - misfire on cylinder 8.

Dropped the car at the shop on Saturday. First tests will be coil pack and spark plugs. Could have done the work at home as well, however the DCT is slighlty leaking and so is the diff, the service is due shortly and hence I decided to just get it all done. Will keep you posted.

Okidoki, sounds good. Better stay in contact with the dealer before they start do the DCT. Depending on where it leaks (can be at least 3 different locations) it can end up being quite costly and you may want to reconsider depending on the amount (most boxes seems to leak some and if small may not be worth while to correct).

Thanks.

At this stage, we are doing the most obvious leak at the pan only - including fluid flush & change.

Basically decided to just do all at once and get back to driving asap

Picked up the car on Friday, all well.

Issue was the coil-pack on cylinder 8, switched them onto cyl 5 - and the issue shifted as well. Had it changed for a new OEM BMW one. Car feels a lot stronger now, seems the system was pulling timing out, after the error was detected first.

Flushing the DCT and replacing the filters had a crazy impact, even at the low mileage I am at.

Good stuff!

The other 7 probably aren’t far behind. I typically swap coils all together, just like bulbs or plugs or tires.

wyatth wrote

The other 7 probably aren’t far behind. I typically swap coils all together, just like bulbs or plugs or tires.

Generally, I would agree, I change tires per axle and spark plugs altogether as well - but with coils, I'm a little bit hesitant as these are not a regular wear&tear item.

Will keep an eye on it - now that I have the code reader stored in the car itself it's easy to check and monitor regularly.

anytime you get a misfire on one cylinder always switch the coil pack to another cylinder. Easiest way to find a bad coil.