Flashing CEL. Loss of power at high rpm

[S4_OUTTY]

Hey all!
I'm having a hard time diagnosing a problem with my car. I've got misfire codes on cylinders two and eight. I've changed spark plugs and coils, and just changed my fuel filter. Codes are still there. The car idles kind of rough sometimes, runs beautifully when accelerating between 1500 - 5000 rpm, but as soon as I accelerate over that mark the CEL flashes and I lose practically all power. The rpms keep spinning but the car will not accelerate anymore. After changing the fuel filter it seemed to alleviate some of the issues. Car runs a bit smoother and starts up better than ever, but the acceleration issue is still the same.
Next step is fuel pump. I'm just wondering if anyone has advice or experience with this. Any other places I should look or any relatively cheap possible fixes before I pony up the cost to take it to the dealer?
Any advice is greatly appreciated!

[Mr. Spectacular]

What did you determine caused your issue?


Sent from my iPhone using Tapatalk

[A.LACK]

I had the same exact problem in my b7s4. Pulled the downpipes and both cats were so bad they didnt even look like cats. Just a solid gray chunk. Gutted both pre-cat and main cats.... problem went away. Idled great and no more high rpm CEL.

[Veeizzlb7s4]

I have a 06, B7 S4 with about 130k i starting getting misfire and loss of power . So i changed the coil and plugs with an after market coil hudson i believe . Afterwards still same so i thought it was the aftermarket coils so i bought dealer oem coils still same what could it be also getting powertrain code

Sent from my SM-N915P using Tapatalk