Naughty A8 - Cyclic revs at low speed, interesting but misleading codes!

[A8Shep]

Hello everyone

I have an 02 D2 2.8 A8 which I would like to start enjoying at some point but there are a couple of things still bothering me with it.

I have had the autobox fully serviced and while it was open had the solenoid valves cleaned as well. Bank 3 had shown as faulty so that was replaced with a delightfully expensive substitute.

Needed a new battery as well so that's sorted.

I also have a Ross-tech VCDS which I used to carry out a throttle body alignment following battery replacement.

NOW - when I travel at a speed that has the revs between 1000 and 1800, it cycles up and down the revs by about 50 each way and it's really irritating; at speed, no problem at all, nor in reverse. I have noticed lately that it hard shifts to 1st when stopping as well.

When I scanned for codes, I got an ABS warning referring to communication to the gearbox was intermittent. I have posted the read out below. I have read in certain places that cleaning the ABS sensors can sort this but could this really be causing my cyclic revs thing? I have also heard of a switch under the gear selector that sometimes goes on the blink.

Trans codes non-existent so can't diagnose any further alone; apart from an O2 sensor issue, engine codes are clear as well.

Anyone suffered this torment? Don't want to give it up so any help is appreciated.

Thanks in advance

Chassis Type: 4D - Audi A8 D2
Scan: 01 03 08 11 15 16 17 18 25 35 37 45 55 56 57 65 67 75 76 77
02

VIN: WAUZZZ4D43N001333
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Address 01: Engine Labels: Redir Fail!
Part No: 3B0 907 551 BT
Component: 2.8L V6/5V G 0001
Coding: 11753
Shop #: WSC 02314
VCID: 76E7E2EB7857
WAUZZZ4D43N001333 AUZ7Z0A2020208


4 Faults Found:
16804 - Catalyst System; Bank 1: Efficiency Below Threshold
P0420 - 35-00 - -
16814 - Catalyst System; Bank 2: Efficiency Below Threshold
P0430 - 35-10 - - - Intermittent
16514 - Oxygen (Lambda) Sensor B1 S1: Malfunction in Circuit
P0130 - 35-10 - - - Intermittent
16534 - Oxygen (Lambda) Sensor B2 S1: Malfunction in Circuit
P0150 - 35-10 - - - Intermittent
Readiness: 0000 0000


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Address 03: ABS Brakes Labels: 8D0-907-389.lbl
Part No: 4D0 907 389 E
Component: ABS/ESP allrad D57
Coding: 08397
Shop #: WSC 02313
VCID: 316D11F7D1B9


1 Fault Found:
01119 - Gear Recognition Signal
35-10 - - - Intermittent


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Address 08: Auto HVAC Labels: 4D0-820-043-MYX.lbl
Part No: 4D0 820 043 P
Component: A8-Klimavollautomat D13
Coding: 00061
Shop #: WSC 02314
VCID: 295DF997F969


No fault code found.


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Address 02: Auto Trans Labels: 01V-927-156.lbl
Part No: 4D0 927 156 DR
Component: AG5 01V 2.8l5V RdW 1818
Coding: 00001
Shop #: WSC 02314
VCID: 7CF3F0C3467B


No fault code found.


End ---------------------------------------------------------------------

 

[A8Shep]

Also perhaps worthy of note is the fact that, whilst the wheels were being balanced, I noticed that the CV boots look past their best. Not sure if a dry CV would cause the issue but I suppose it's worth mentioning everything