Misfire cylinder 7 after replacing injector, plug, and coil

[flippnswitchez]

I have an 09 S5 with 140k The car has been pretty solid. I keep it maintained. I did a carbon cleaning on it. I recently got I misfire on cylinder 7. I can swap the coil and stays on 7. I have replaced the plug, coil, and injector. It is still present as soon as I start the car. I can clear the code and it comes right back. It idles ROUGH. Any ideas?

[TontoLoidRS5]

Looking around a bit you will find accounts of this happening after carbon clean up. The fix apart from obvisouly replacing the injector, is on some accounts some, replacing all injectors I am afraid based on something I don't quite understand. Sry this happened, all i know you don't want a faulty injector.

[BuyTheWarranty]

Straight from Audi: You are to replace ALL injectors and seals when doing a carbon clean.

I have now seen 10+ accounts of this issue post carbon cleaning where people only replaced 1 (or none) resulting in misfires including myself. I have a B8.5 RS5.

[flippnswitchez]

I have replaced all and still have a misfire.

[flippnswitchez]

Turns out low compression. Only 80psi for both wet/dry test

[nhracecraft]

That doesn't sound good...Any idea on what happened to cause you're issue? I performed a Carbon Clean on my '10 S5 4.2 V8 at 142K over the summer and I did walnut media blasting. It was a BIG project! Perhaps some walnut media end up getting into the cylinder(s)? Wondering if you got it sorted out...