A4audigirl

Hi guys,

My 2008 Audi A4 has been misfiring and found out there's carbon build up in the valves. My mechanic said the fuel injectors need to be replaced and the valves need to be cleaned out. I know this is a common problem for direct injection. What would the average pricing be for this type of job? Do the injectors really need to be replaced? Couldn't they just be cleaned? (apologies if this has been asked before, I couldn't find the info searching online).

Caseyj955

I'm new to Audi also with an 06 A4, but I have been around German cars for a helluva long time. I'm also facing the decarbon service, at 170k I have very little service history and missing some top end performance but runs well. I'm not sure how the carbon buildup could trigger a missfire, but it will impede flow and rob performance after awhile. A missfire could be an injector, and about a million other things. Did you have it to a trusted shop or a stealership? There is an index here that discusses trusted shops so definitely try and find one of those. I use RCS tuning in Loveland CO, and I have to drive from South Dakota to do so. Thats how important it is to have the right people work with your car. I know there is a load of them in the LA area, there has to be.

The buildup happens in the DI engines because the fuel is injected directly into the cylinder and does not pass the valves as it does on port injected cars (most all cars on the road today) I have read that the PCV hurries the buildup. Because the intake valves never see the fuel than no additives or detergent fuels are able to impact this. As I have researched it's just a normal part of routine maintenance on these Direct Injected cars. I'll do mine myself but I have read quotes ranging from about $500 to way the hell up there. So yea, get a 2nd opinion on the injectors and make sure your taking it to a place the other Audi/VW guys endorse.

How many miles does your car have and do you have a service history indicating if/when it was last done?

What I want to know is if a boroscope can be snaked into the intake to get a visual on the intake valves without disassembly. Although I know pulling the intake for this service is not that tough of a job. Good luck.