@udi4.qwick

Where do I start looking for problems? MAF?

Could K&N drop-in air filter caused it?

O2 sensor?

Air-leak?

This is what I got after I scanned with vag-com last night:

Chassis Type: 4B - Audi A6 C5
Address 01: Engine
Controller: 4D0 907 560 AE
Component: 4.2l V8/5V G 0003
Coding: 07752
Shop #: WSC 02325
xxx xxx
3 Faults Found:
17549 - Load Calculation Cross Check: Implausible Value
P1141 - 35-10 - - - Intermittent
17539 - Oxygen (Lambda) Sensor; B2 S1: Internal Resistance too High
P1131 - 35-10 - - - Intermittent
17819 - Secondary Air Injection System; Bank 2: Insufficient Flow
P1411 - 35-00 - -
Readiness: 0000 0000

-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
Address 35: Centr. Locks
Controller: 4B0 962 258 J
Component: Central Lock/Alarm D34
Coding: 15981
Shop #: WSC 02325
7 Faults Found:
01371 - Alarm triggered by Door Contact Switch; Driver's Side
35-00 - -
01374 - Alarm triggered by Terminal 15
35-00 - -
01370 - Alarm triggered by Interior Monitoring
35-00 - -
00955 - Key 1
09-10 - Adaptation Limit Surpassed - Intermittent
01559 - Drivers Door
58-10 - Can't Lock - Intermittent
01562 - Right Rear Door
58-10 - Can't Lock - Intermittent
01574 - Alarm triggered by Door Contact Switch; Right Rear
35-00 - -

-------------------------------------------------------------------------------
Address 45: Inter. Monitor
Controller: 4B0 951 178 A
Component: Innenraumueberw. D04
Coding: 00101
Shop #: WSC 02325
1 Fault Found:
01349 - Alarm via Theft Warning System; Front
35-00 - -

Kimchee

MAF, O2 and then looks like battery was disconnected recently