1.8t vibrating at idle

[myth]

Hello again everyone,

So my girl has an Audi A3 1.8t AUM and at idle there is a strong vibration inside the car, that seems to come from... everywhere. As soon as you pass 1000rpm, the vibrating is gone. I have also tried to raise the idle but it doesn't pass that point where everything is smooth.

There are no fault codes, the spark plugs are new. Also tried with other ignition coils.

Could it be a failing dual mass flywheel?

 

[Daniel M]

Engine/gearbox mounts possibly?

 

[mr_pepps]

Is it like a misfire vibration?
I had that - cured by replacing the ignition control amplifier (little oval box fixed to the rear of the air box).

 

[myth]

No, it's not a misfire vibration. Also, that would throw an error code, but it doesn't.
Do you have a picture of the said part? I don't know what are you referring to.

@daniel, not sure. They seem fine to me, even the dogbone.

 

[mr_pepps]

@myth Here's a pic of the item from the Haynes manual. Hopefully this helps.
I changed this unit on my A3 to cure a misfire/vibration. About £25 for a second hand unit on eBay.

Before I changed this I swapped all plugs and refreshed all the breather hoses/valves. Ahh well. I guess the car benefitted from all the new parts.

 

[myth]

I have no such thing on the air filter housing.

But I have found the problem. It seems to be the DMF fail. With one wheel off the ground and in gear, this is the play in the flywheel:

 

[mr_pepps]

@myth Ah sorry mate, must be the AGU/AUM difference. Hope the fix isn't too much of a faff.

 

[myth]

So I have replaced the DMF with SMF and there is an improvement, but not as I imagined. Still vibrating, still annoying...
During the job I checked the engine and gearbox mounts and seems fine to me.

So, what to check next?