My A6 S-Line 2.7T doesn't seem to have consistent power. Sometimes it loves to go, but much of the time it takes its sweet time to get up to speed. I did a VAG-COM dump and got the following codes awhile back. I've put new coils, plugs, and wires on it since doing this scan, but I wonder if any of these are still relevant. I worry that it might be the turbos. God I hope not...

17831 Secondary air injection system, bank 1
P1423 - 35 - 00 Insufficient flow

17965 Charge pressure control
P1557 - 35 - 00 Positive Deviation

17545 Fuel trim: Bank 1
P1137 - 35 - 10 System too rich - intermittent

17547 Fuel trim: Bank 2
P1139 - 35 - 10 System too rich - intermittent

17819 Secondary air injection system, bank 2
P1411 - 35 - 00 Insufficient flow

17887 Brake boost vacuum System
P1479 - 35 - 10 Mechanical failure - intermittent

17535 Fuel trim; bank 1 mult
P1127 - 35 - 10 System too rich - intermittent

17537 Fuel trim; bank 2 mult
P1129 - 35 - 10 System too rich - intermittent

 

You more than likely have a vacuum leak somewhere and your secondary air injection pump either isn't working anymore or the air is not reaching the EGR valves.

Correct the SAIP issues first, clear the codes and go for a test drive and see what - if anything - comes back up. Then go hunting for the vacuum leak, which might be present around the brake booster / jet suction pump.

None of these codes indicate that your turbos are acting up.