Misfire on cylinder 2

[dmc_s3_8p]

Hi all, I'm trying to track down a misfire issue with my stock 2008 S3 8P on 106,000 miles. It started to run a little rough on idle and the mpg dropped down by about 5mpg at the same time. Once it warms up the rough idle issue almost disappeared.

I changed the plugs (NKG) and then new Bosch coil packs and there is a misfire on cylinder 2. There's no engine light and I've swapped the plugs and coil packs around and the misfire remains on cylinder 2.

I've got a full version of vcds and the only error showing in the engine is this misfire. I was wondering if there was any way of checking whether injector 2 was starting to fail or what to check next.

Thanks.



Sent from my Nokia X20 using Tapatalk

 

[lafa3ro]

I had the exact same symptoms and it was all due to carbon build up. Might be worth checking the valves with a bore scope.

Envoyé de mon Pixel 4a en utilisant Tapatalk

 

[dmc_s3_8p]

I had the exact same symptoms and it was all due to carbon build up. Might be worth checking the valves with a bore scope.

Envoyé de mon Pixel 4a en utilisant Tapatalk

Interesting! Did you get a walnut blast / carbon clean and did that solve it? The car had sat for a week or so in the cold just before this happened and was on a tank of E10 fuel (not the best plan!) Thanks.

Sent from my Nokia X20 using Tapatalk

 

[lafa3ro]

Yeah the dealer did a carbon removal (can't remember which method they used) and all had been good since, 6 years later.

Envoyé de mon Pixel 4a en utilisant Tapatalk

 

[lafa3ro]

Although I had a one off lately after the car sat for 2 weeks in the cold. Car started with a jumper pack and then was misfiring so bad it shut down one cylinder. Once the car warmed up and I cleared the safe mode all was well.

Envoyé de mon Pixel 4a en utilisant Tapatalk

 

[S.]

Does it burn oil?
At that mileage it's worth doing carbon cleanup and sending injectors for testing and refurbishing...

 

[dmc_s3_8p]

Does it burn oil?
At that mileage it's worth doing carbon cleanup and sending injectors for testing and refurbishing...

It's not really burning any more oil than usual. I'm coming round to the idea that it needs a good carbon clean and injectors tested/refurbished like you say.

It sat most of the winter and only really had shortish journeys which probably hasn't helped.

Sent from my Nokia X20 using Tapatalk