Audi S8 D2 misfire Lambda sensor fault

[richyb66]

I'm not convinced that the lamba fault would cause a misfire either.

You say the misfire is noticeable at idle but are there any other symptoms when it's running normally? I had a "misfire" at idle and the car felt a bit down on power - no relevant codes were stored. After swapping a few bits and having a bit of a think, I finally tracked it down to a faulty fuel pump. The old pump was causing a fluctuation in fuel pressure that was causing the car to run poorly and it had seemed more noticeable at idle for some reason.

[Architex_mA8tey]

I was just going to say check the fuel system and pump! good call

[Goran]

As Mike says, front lambdas can be reached from above the engine by removing the Secondary air injection kombi valves (metal mushrooms on back of engine block). My local mechanic changed both of my front labmdas this way in less than 1 hour. No exhaust dropping necessary.

[ainarssems]

The fault code is for heating element of lambda sensor, very unlikely to cause misfires. The sensor in question is precat on the downpipe. Not sure about 40V but on 32V it's fairly accessible from the top if you have lambda sensor socket also there is not much space.

If you have VCDS check the measuring blocks for misfires to see if they are random or mostly on 1 cylinder or on 1 bank.