I have a 05 B6 S4 with 130,000 on it. I'm throwing codes p0300, p0305, p0306, p0307, p0308. I'm assuming that's all one bank, but I also have a p0171 code which is lean fuel supply bank one. I'm pretty sure all of those misfires are bank two though so that's confusing. Also, every time I rev the engine significantly (over 6,000 at idle and over 5k while driving) I lose pretty much all power and the rpms pin and my mph drop.
I had it in to a shop and they said it was spark plugs and coils, they changed those with no help. Once I got the car back I changed the fuel filter, fuel pump, air filter, and cleaned the MAF sensor and just gave it an oil change.
If anyone has any advice or insight it'd be greatly appreciated. I'm pulling my hair out here and I'm scared a shop will just charge big bucks to take a stab at the spark plugs and coil packs again.
Thanks guys!