Jerk at moderate throttle e92 6MT

[xcharlesy]

So I went to the dealer in an attempt to get my software updated, as I thought this was what people were describing was an issue.. it never bothered me, as when I bought the car it behaved the same, and I chalked it up as how the car acts.

After driving it with the foreman, he said he's seen a similar issue in another car that needed a cool pack, he said it behaved the exact same way, and he was able to do it enough that it eventually scanned a code, so he told me he'd keep my car over night and scan it, and attempt to make it throw a code, which is evidentially didn't, and no codes came back, although still persistent, he's going to replace it right now.

From what I've read it could be one of a few issues..

I was thinking - software, coil pack causing misfire, or diff bolt?

The best way to describe the problem, it's in most gears 2-6 I can apply moderate to a lot to full throttle and it has an initial little snap before it begins to accelerate, you can sort of here it, and you can definitely feel a little pop or jerk for a second before it begins to accelerate. The car is a 08 e92 M3 with 57,000 miles.

Never had a single issue since I bought it..

I suggested them to check diff bolts, but the service manager is a majorly incompetent and insists I'm wasting his time with what I've learned online.

Any help would be greatly appreciated!

[M3amigos]

Are you covered under warranty? Hopefully they aren't taking stabs in the dark on your dime. If you aren't satisfied with the service certainly find another dealer/shop.

I've had worn/damaged differential mounts in a previous car and it was a clear thump in the rear of the car every time I applied throttle. It was most evident when I was at low speeds, applying throttle in a higher gear. Not sure if this helps or not.

You may be on the right track with the software or coil pack, another thing to think about is your spark plugs. Have you changed them yet? If not, I would definitely replace them.

If the jerking is still there when you get the car back, try to listen and determine if its a drivetrain problem or engine problem. Maybe have someone outside the car listen to see see if its more of a drivetrain clunk vs an engine hesitation. Hopefully its not your tranny or diff. Good luck!

[xcharlesy]

I'm under full warranty, however I'm a little astonished that a BMW shop format, can't identify this within 2 work days.

[xcharlesy]

just heard back from BMW and they replaced the ignition coil pack, they apparently figured it was a misfire in #6? but I had no code thrown.... Basically I was told that the shop foreman sent data to some BMW techs and they both came to the conclusion to do this?

can anyone elaborate on this? it's not really adding up to me

[Lute__]

Coilpack is an easy fix, if this was the cause consider yourself lucky

[xcharlesy]

going to pick up the car in an hour and I'll report back,

could this really have been a problem without a code?

[xcharlesy]

problem resolved

[M3amigos]

Good to hear you got it resolved...