SFD732

Car was running well, was out running some errands, had stopped a few places with no issue. Ran to the grocery store to grab 2 or 3 things, no more than 10 minutes, started car and immediately went to misfires. I limped it home 2 miles or so, I assumed a coil pack. Scanned via vag-com and it had misfires on 3 cylinders. Found that super odd but it is a Audi. Cleared the codes and multiple misfires again. Looked over some things, had a friend come and also look just to see if I was missing something. My guess was HPFP due to hot start issues on maybe 3 occasions. I finally got around to swapping HPFP and no change. I am attaching scans both after sitting over winter and what immediately came back up after I cleared the codes.

In my thoughts, though it may need coil packs or plugs why all 4 cylinders at once? If it was the turbo I'd assume only issues in boost.

Any advice on where to start is appreciated.



First scan is after battery died over winter , wanted to include a pre reset scan just in case something popped out in the engine section. Post below is from after a fault code reset.

--------------------------
Address 01: Engine (------CGTA) Labels:. 079-907-560-CFS2.clb

10 Faults Found:
4629 - ECM Power Relay Load Circuit
P068A 00 [01100000] - Opens Too Early
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Date: 2000.00.00
Time: 00:00:00

Engine RPM: 0.00 /min


17262 - Terminal 30
U140A 00 [00100000] - Open Circuit
[New feature! Extended UDS fault detail is only supported by current gen. interfaces]
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1

Engine RPM: 0.00 /min


10544 - Cold Start Ignition Timing Performance
P050B 00 [01100101] - -
Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 97200 km
Date: 2024.05.18
Time: 13:04:08

Engine RPM: 1307.50 /min


17901 - Fuel Rail/System Pressure
P0088 00 [01100000] - Too High
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 97200 km
Date: 2023.12.05
Time: 12:30:39

Engine RPM: 666.50 /min


10203 - Random/Multiple Cylinder Misfire Detected
P0300 00 [11101101] - -
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 97200 km
Date: 2023.12.05
Time: 12:28:16

Engine RPM: 705.50 /min


10591 - Cylinder 1
P0301 00 [11101101] - Misfire Detected
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 2
Mileage: 97200 km
Date: 2023.12.05
Time: 12:28:16

Engine RPM: 705.50 /min


10594 - Cylinder 4
P0304 00 [11101101] - Misfire Detected
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 97200 km
Date: 2023.12.05
Time: 12:28:16

Engine RPM: 705.50 /min

10593 - Cylinder 3
P0303 00 [11101101] - Misfire Detected
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 97200 km
Date: 2023.12.05
Time: 12:28:16

Engine RPM: 705.50 /min

10592 - Cylinder 2
P0302 00 [11101101] - Misfire Detected
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 97200 km
Date: 2023.12.05
Time: 12:28:51

Engine RPM: 1117.50 /min


10205 - Cylinder Disabling
P130A 00 [00101100] - -
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 3
Mileage: 97200 km
Date: 2023.12.05
Time: 12:28:49

Engine RPM: 1814.00 /min


Readiness: 1110 1101

-----------------------------------------------------------------------------

SFD732

this is the 2nd scan, previous scan was after battery being dead over winter and new battery going in

Saturday,18,May,2024,13:19:26:19186


Address 01: Engine (------CGTA) Labels:. 079-907-560-CFS2.clb


6 Faults Found:
10203 - Random/Multiple Cylinder Misfire Detected
P0300 00 [01100101] - -
Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 97200 km
Date: 2024.05.18
Time: 13:16:06

Engine RPM: 717.50 /min


10591 - Cylinder 1
P0301 00 [01100101] - Misfire Detected
Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 97200 km
Date: 2024.05.18
Time: 13:16:06

Engine RPM: 717.50 /min


10594 - Cylinder 4
P0304 00 [01100101] - Misfire Detected
Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 97200 km
Date: 2024.05.18
Time: 13:16:11

Engine RPM: 659.00 /min


10593 - Cylinder 3
P0303 00 [01100101] - Misfire Detected
Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 97200 km
Date: 2024.05.18
Time: 13:16:06

Engine RPM: 709.00 /min


10592 - Cylinder 2
P0302 00 [01100101] - Misfire Detected
Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 97200 km
Date: 2024.05.18
Time: 13:16:43

Engine RPM: 1024.50 /min


10205 - Cylinder Disabling
P130A 00 [00100100] - -
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 97200 km
Date: 2024.05.18
Time: 13:16:42

Readiness: 1110 1101

-------------------------------------------------------------------------------

DallasDave

When was the last time you did change the spark plugs? The service interval is really short, like 30k miles. If you haven't done it or haven't done it in a really long time, I'd start there. Take our a plug from one of the offending cylinders and see what you find.

SFD732

I will pull the plugs and change them tonight or tomorrow. I have only owned the car for like 8k and in that time have had nothing but problems.

Bose amplifier blew
passenger mirror stuck up
pcv system recall due to dreaded whistle
oil strainer recall
driver side front air strut hole in bag
upper window seal leak (windshield replaced)
tire sidewall bubbled
currently also has slow coolant leak from 1 of the thermostat pipes

i know the driver side hpfp was done shortly before I purchased the car. God I wish I had gone another route with this car purchase. I have never had issues like this with any of the VAG cars I have owned. I assumed low mileage and a decent service record equated to semi reliability.

mikesvwservice

Please let us know of your outcome...

Sorry to hear of your issues - maybe things will get better!

I have a 2013 A8L 4.0T with an APR Stage One tune and it "feels" like I have a subtle "miss" when I get on it to pass cars from 80 to 105 mph - not getting "linear" and smooth power delivery and I need to scan and investigate further (car is rarely driven)...

MP4.2+6.0

For OP: FWIW, I try to help but am NOT interested in doing free reading of totally unedited scans--way, way too long. Please cut it down first to relevant modules and where there are faults.

A8L_New_England

.
lol, MP, I thought the same. At first I was wondering crank sensor, or something, then... man, I don't have time for this
.

SFD732

I apologize. In the past I have seen people ask for full scans. I assumed that was what everyone wanted.. In my mind the only relevant area is the engine. I cut it down for everyone.

MP4.2+6.0

Thanks. Better.

First ideas are

• plugs--hence others asking on tune up. D4 (stock) is/was 40K miles on plugs after first change. On newer 4.OT's, Audi now says 30K.
• an HPFP driving it lean
• Vacuum leak--notice all the misfires are on one side (USA passenger), which may point to a leak somewhere nearer to that side.
• Sensor. Don't always assume the normal data inference itself is right.
• Lesser case. Bad (pre-cat) O2 or similar sensor on that side that is throwing off the sensor read mixture and causing ECU to drive it lean on that side (bank).

Unlikely: Coil packs (with that many all at once seeming very unusual absent flood damage or something weird).

Bonus corner case points: Known PCV/oil separator 4.0T fail point maybe going bad. Don't know how it ties in by side or if you can get vacuum leak type symptoms. I just convinced dealer to do mine at tail end of service bulletin (10 years or 100K extended warranty). You have clocked out there, but if never changed keep an eye (ear) out. If you hear the "whistle", that's a big clue.

If I were going to try an educated guess and throw limited parts at it--that don't really go to waste anyway--I would perhaps try plugs and a new pre-cat O2 sensor on USA passenger side. OES Bosch O2's are not very expensive and plug n play. I lost my first O2 on my 2015 S8 by 55K miles or so, I had lean codes though that made it a more direct decent guess.

A8L_New_England

.
Given that the misfires are all on one bank, all at once, forget plugs and coils. You didn't mention how it ran under higher load... You should be able to include or exclude considering an air leak from that. I'd have a look at the sensors which control on a per-bank basis - pre-cat O2 like MP suggested, cam-position sensors, and the like. I'd also consider per bank devices beyond the hpfp... have you checked the turbo?
.