a_alyte

I have had plastics break on me so I know what you mean, I noticed a few pieces broken before I purchased as well. It does make sense to swap all 8 while there being accessed, its currently at the shop and I'm waiting to hear what the mechanic thinks. If they suspect carbon do you think I should just swap all injectors and let the carbon be, since carbon will always be present?

rome5982

I removed the intake manifold and found that all of my valve intakes were extremely carbon/oiled fouled. You could barely see the intake valve stems. Did some reading and found out that this is a common problem with the earlier generation FSI direct injection cars (especially from VW and Audi). I did a manual cleaning of each cylinder intake area scraping and vacuuming away all of the gunk, then using seafoam and soaking the valves and then more ceaning, scraping, vacuuming. While I was in there I went ahead and replaced the #6 fuel injector (just in case). Needed to purchase a special high pressure injector removal tool because those injectors are pressed in there good. Put everything back together and runs like a champ, no CEL's and much better/smoother acceleration and power. I will be posting a DIY and pictures soon.

On a side note, I had already replaced the intake manifold adapter piece that goes between the intake manifold and the throttle body because of a brittled/cracked plastic piece that was causing a coolant leak prior to the misfire problem - so I can vouge for the cheap plastic problem in some of the areas of the engine.

What a shame that a $90K car will have such carbon fouling issues with only 75K miles.

Before

rome5982

After

a_alyte

Thanks for the pics. This could easily be my problem as well. It's definitely a shame the valves on these cars get so fouled. I guess its just a maintenance item for those of owning long term.

mishar

All those deposits won't really make any noticeable performance difference unless you are chasing last drop of power. It won't cause misfire for sure. But source of that oil is important. Unless you find it deposits will be back soon.

greginfinity

Are you sure about that? I had an A6 Avant with the 3.2 (known for that sort of valve gunk), and it threw a CEL. Got rid of the car before I really tracked it down, but the dealer gave the obligatory "drive it hard" speech.

If the valves don't seat properly because if said gunk, I think you would definitely have issues. Air would be able to escape during the compression stroke, and who knows during ignition.

Thanks for keeping us updated!

a_alyte

Ok guys, I finally have something to report. I left the car with my 'new' mechanic who called me to come in as soon as he had the manifold removed. He wanted to show me how one of the manifold bolts was cracked due to over torquing, luckily this did not sacrifice the integrity of the manifold. Secondly, he pointed out that the oil separator was loose and not connected properly, it also did not have the spring action that it should. Part of the oil separator fell apart when he removed it. He replaced the oil separator and number seven injector and also cleaned the valves. The valves were dirty but not severely, sorry no pics. The number seven injector may not have been the problem but it made sense to change it since the manifold was removed.

When I picked the car up I noticed immediately upon starting how smooth the idle was. I hit the highway for a few miles and quickly realized what I've been missing, the car accelerates like its ready to play. I chose not to replace the other seven injectors as a precautionary measure so fingers crossed on that one. I appreciate the many responses to this thread and hopefully it can help someone else.

Oneplank

Make sure to patronize that technician. He appears to understand Audi's and can spot botched previous repairs. I think you can stop worrying about oil fouling now that he found the problem with the separator. Glad to hear the engine is running well and wishing you the best of luck with the other 7 injectors.

a_alyte

With the manifold removed there was evidence of an oil leak as well. The mechanic changed the gaskets for the oil filter housing while he was in there.