2008 4.2L C6 Multiple Misfires and Running Rough Please Help

[Formula76]

Hello, please read this over and any help you can offer would really be appreciated. I've been chasing this around and done all the testing I can without replacing any new sensors etc. The car has been smoke tested using a professional grade machine in the last few days. No leaks.


So I have this issue that has been happening for a while now...as a result the car has not really been driven much and I have been driving my other Audi.

This 2008 A6 4.2L Multiple misfires most the time after a little while when test driving. Yellow check engine light comes on, blinking, then usually constant. It will drive fine after I clear the codes, but then after a short time it will start running rough and the same cycle will repeat which is normal for the problem not being resolved...

I have Ross Tech VCDS so I have run many reports over the last few months. It has lost power a couple times and I am aware of the voltage issues, etc. that are created from that and I clear the codes and keep trying to focus on the misfire and check engine warning issues.

Five Days Ago, I have the same ongoing issue as I drove to my friends shop to smoke test it because I was told I have a vacuum leak. My Engine Measuring blocks are all over the place with fuel mixture issues where it runs weird and I believe bad mileage, and if I clear the codes it wont run rough until it goes wacko again, running rough and the whole process repeats. 5 days ago I documented:

So this data is all I have from this reoccurring problem(s). Any help you can give would be really appreciated.

Main Engine Faults are coming usually from cylinders #1 and #7, or sometimes a new report and I get one on cylinder #4, previously some time ago I have had it on all of them, #1, #4, #7. I also sometimes get this 008753 - Oxygen (Lambda) Sensor B1 S1 code fault (see snippet from the report):

008753 - Oxygen (Lambda) Sensor B1 S1
P2231 - 004 - Signal Shorted to Heater Circuit - Intermittent
Freeze Frame:
Fault Status: 00100100
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 166986 km
Time Indication: 0
Date: 2007.03.08
Time: 14:45:00
Freeze Frame:
RPM: 3315 /min
Load: 92.9 %
Speed: 104.0 km/h
Temperature: 74.0°C
Temperature: 9.0°C
Absolute Pres.: 1020.0 mbar
Voltage: 13.589 V
000772 - Cylinder 4
P0304 - 001 - Misfire Detected - MIL ONVCDS
Self-Diagnosis Log
Wednesday,17,March,2021,17:41:00:02327
Page 5

Freeze Frame:
Fault Status: 11100001
Fault Priority: 2
Fault Frequency: 2
Reset counter: 255
Mileage: 166986 km
Time Indication: 0
Date: 2007.03.08
Time: 14:45:04
Freeze Frame:
RPM: 2678 /min
Load: 63.9 %
Speed: 112.0 km/h
Temperature: 74.0°C
Temperature: 9.0°C
Absolute Pres.: 1020.0 mbar
Voltage: 13.589 V
Readiness: 0010 1100

My spark plugs are less than 10k old, I have troubleshot my coils previously and replaced one.

When I did my valve covers recently I cleaned the oil out and cleaned all the spark plugs again. I've done this a few times in the last 10k, although I haven't done this recently in the last few months.

It was running so rough last week (as it has for a few months) I was concerned about driving it. I fired it up and limped the drive to my friends garage where in transit I managed to get all the codes cleared after a few rounds (three sets of scans and clears because it took 3x to do so, the last 5 miles it ran fine after clearing faults of course so as I limped it there about 10 miles away total). By the time I got there I was running a clean report, no check engine light and I arrived and smoke tested it with a professional machine with UV mineral oil to check for vacuum leaks. I had no leak issues during the smoke test. No leaks and still no codes as I ran reports again. Car ran fine with no faults. Drove it home fine with no issues.

The next day I hopped in and after about .25 miles it repeated all the same core problems repeating as before: rough running, misfires, check engine light coming on, etc. This is the same reoccurring pattern. Not really drivable. Once again, I turned it around and parked it. Ran my report and it just came up with just one misfire this time on cylinder #4 opposed to the previous reports of cylinders #1 and #7, and I also have another fault code of 008753 - Oxygen (Lambda) Sensor B1 S1
P2231 - 004 - Signal Shorted to Heater Circuit - Intermittent as I mentioned above.

Here are the before and after smoke testing reports. As I said I also checked out the changes on the engine measuring blocks that did lots of correcting after codes are cleared. Definitely attempting to compensate but I do not claim to be an expert on this. My friend told me I just had a vacuum leak causing all of this but I thoroughly checked it it out and saw absolutely nothing. Here are the reports from on the way to the shop and then tonight's as it failed again:



5 days ago pre-smoke testing and before I cleared all the codes:

VCDS
Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: Release 21.3.0(x64) Data version: 20210226 DS325.0
www.Ross-Tech.com
Dealer/Shop Name:
Workshop Code: 000 00000 000000
Self-Diagnosis Log
Wednesday,17,March,2021,17:41:00:02327

Mileage: 167000km-103768mi Repair Order: 1
Chassis Type: 4F (4F0)
Scan: 01 02 03 05 07 08 09 0E 0F 15 16 17 19 1E 36 37 42 46 47 4F
52 53 55 56 61 62 65 72 77

00-Steering Angle Sensor -- Status: OK 0000
01-Engine -- Status: Malfunction 0010
02-Auto Trans -- Status: OK 0000
03-ABS Brakes -- Status: Malfunction 0010
05-Acc/Start Auth. -- Status: Malfunction 0010
07-Control Head -- Status: Malfunction 0010
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: OK 0000
0E-Media Player 1 -- Status: OK 0000
0F-Digital Radio -- Status: Malfunction 0010
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: Malfunction 0010
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: Malfunction 0010
1E-Media Player 2 -- Status: OK 0000
25-Immobilizer -- Status: Malfunction 0010
36-Seat Mem. Drvr -- Status: Malfunction 0010
37-Navigation -- Status: Malfunction 0010
42-Door Elect, Driver -- Status: OK 0000
46-Central Conv. -- Status: Malfunction 0010
47-Sound System -- Status: Malfunction 0010
4F-Centr. Electr. II -- Status: OK 0000
52-Door Elect, Pass. -- Status: OK 0000
53-Parking Brake -- Status: OK 0000
55-Headlight Range -- Status: OK 0000
56-Radio -- Status: OK 0000
61-Battery Regul. -- Status: Malfunction 0010
62-Door, Rear Left -- Status: OK 0000
65-Tire Pressure -- Status: Malfunction 0010
72-Door, Rear Right -- Status: OK 0000
77-Telephone -- Status: Cannot be reached 1100
-------------------------------------------------------------------------------VCDS
Self-Diagnosis Log
Wednesday,17,March,2021,17:41:00:02327
Page 2

Address 01: Engine Labels:. 079-907-560-BVJ.clb
Part No SW: 4F1 910 560 E HW: 4F1 907 560
Component: 4.2l V8/4V 0010
Revision: 74H04--- Serial number:
Coding: 01050009190F0120
Shop #: WSC 02335 758 00200
VCID: 2517F2E939E19753DC5-8070
8 Faults Found:
000768 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - - MIL ON
Freeze Frame:
Fault Status: 11100001
Fault Priority: 2
Fault Frequency: 3
Reset counter: 255
Mileage: 166851 km
Time Indication: 0
Date: 2021.01.07
Time: 22:43:52
Freeze Frame:
RPM: 2678 /min
Load: 63.9 %
Speed: 112.0 km/h
Temperature: 74.0°C
Temperature: 9.0°C
Absolute Pres.: 1020.0 mbar
Voltage: 13.589 V
000769 - Cylinder 1
P0301 - 001 - Misfire Detected
Freeze Frame:
Fault Status: 01100001
Fault Priority: 2
Fault Frequency: 2
Reset counter: 255
Mileage: 166851 km
Time Indication: 0
Date: 2021.01.07
Time: 22:43:52
Freeze Frame:
RPM: 678 /min
Load: 23.9 %
Speed: 0.0 km/h
Temperature: 47.0°C
Temperature: 18.0°C
Absolute Pres.: 1010.0 mbar
Voltage: 14.097 V
000773 - Cylinder 5 VCDS
Self-Diagnosis Log
Wednesday,17,March,2021,17:41:00:02327
Page 3

P0305 - 008 - Misfire Detected - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 166851 km
Time Indication: 0
Date: 2021.01.07
Time: 22:43:52
Freeze Frame:
RPM: 640 /min
Load: 31.4 %
Speed: 0.0 km/h
Temperature: 72.0°C
Temperature: 50.0°C
Absolute Pres.: 1010.0 mbar
Voltage: 14.351 V
000775 - Cylinder 7
P0307 - 008 - Misfire Detected - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 166851 km
Time Indication: 0
Date: 2021.01.07
Time: 22:43:52
Freeze Frame:
RPM: 640 /min
Load: 31.4 %
Speed: 0.0 km/h
Temperature: 72.0°C
Temperature: 50.0°C
Absolute Pres.: 1010.0 mbar
Voltage: 14.351 V
005634 - Power Supply Terminal 30
P1602 - 002 - Voltage too Low - Intermittent
Freeze Frame:
Fault Status: 00100010
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 0 km
Time Indication: 0
Freeze Frame:VCDS
Self-Diagnosis Log
Wednesday,17,March,2021,17:41:00:02327
Page 4

RPM: 0 /min
Load: 0.0 %
Speed: 0.0 km/h
Temperature: -40.0°C
Temperature: -40.0°C
Absolute Pres.: 0.0 mbar
Voltage: 0.000 V
005715 - Please check DTC Memory of ABS Controller
P1653 - 008 - - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 2
Fault Frequency: 2
Reset counter: 255
Mileage: 166929 km
Time Indication: 0
Date: 2007.03.02
Time: 12:03:36
Freeze Frame:
RPM: 1087 /min
Load: 44.3 %
Speed: 0.0 km/h
Temperature: -1.0°C
Temperature: 2.0°C
Absolute Pres.: 1000.0 mbar
Voltage: 11.176 V
008753 - Oxygen (Lambda) Sensor B1 S1
P2231 - 004 - Signal Shorted to Heater Circuit - Intermittent
Freeze Frame:
Fault Status: 00100100
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 166986 km
Time Indication: 0
Date: 2007.03.08
Time: 14:45:00
Freeze Frame:
RPM: 3315 /min
Load: 92.9 %
Speed: 104.0 km/h
Temperature: 74.0°C
Temperature: 9.0°C
Absolute Pres.: 1020.0 mbar
Voltage: 13.589 V
000772 - Cylinder 4
P0304 - 001 - Misfire Detected - MIL ONVCDS
Self-Diagnosis Log
Wednesday,17,March,2021,17:41:00:02327
Page 5

Freeze Frame:
Fault Status: 11100001
Fault Priority: 2
Fault Frequency: 2
Reset counter: 255
Mileage: 166986 km
Time Indication: 0
Date: 2007.03.08
Time: 14:45:04
Freeze Frame:
RPM: 2678 /min
Load: 63.9 %
Speed: 112.0 km/h
Temperature: 74.0°C
Temperature: 9.0°C
Absolute Pres.: 1020.0 mbar
Voltage: 13.589 V
Readiness: 0010 1100
------------------------------------------------------------------------------- Address 02: Auto Trans Labels: 09L-927-760.lbl
Part No SW: 4F5 910 156 A HW: 09L 927 156 C
Component: AG6 09L 4,2 FSI USA 0010
Revision: --H03--- Serial number: 4339229
Coding: 0000002




00-Steering Angle Sensor -- Status: OK 0000
01-Engine -- Status: Malfunction 0010
02-Auto Trans -- Status: OK 0000
03-ABS Brakes -- Status: Malfunction 0010
05-Acc/Start Auth. -- Status: Malfunction 0010
07-Control Head -- Status: Malfunction 0010
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: OK 0000
0E-Media Player 1 -- Status: OK 0000
0F-Digital Radio -- Status: Malfunction 0010
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: Malfunction 0010
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: Malfunction 0010
1E-Media Player 2 -- Status: OK 0000
25-Immobilizer -- Status: Malfunction 0010
36-Seat Mem. Drvr -- Status: Malfunction 0010
37-Navigation -- Status: Malfunction 0010
42-Door Elect, Driver -- Status: OK 0000
46-Central Conv. -- Status: Malfunction 0010
47-Sound System -- Status: Malfunction 0010
4F-Centr. Electr. II -- Status: OK 0000
52-Door Elect, Pass. -- Status: OK 0000
53-Parking Brake -- Status: OK 0000
55-Headlight Range -- Status: OK 0000
56-Radio -- Status: OK 0000
61-Battery Regul. -- Status: Malfunction 0010
62-Door, Rear Left -- Status: OK 0000
65-Tire Pressure -- Status: Malfunction 0010
72-Door, Rear Right -- Status: OK 0000
77-Telephone -- Status: Cannot be reached 1100
-------------------------------------------------------------------------------VCDS
Self-Diagnosis Log
Monday,22,March,2021,21:01:11:02327
Page 2

Address 01: Engine Labels:. 079-907-560-BVJ.clb
Part No SW: 4F1 910 560 E HW: 4F1 907 560
Component: 4.2l V8/4V 0010
Revision: 74H04--- Serial number:
Coding: 01050009190F0120
Shop #: WSC 02335 758 00200
VCID: 2517F2E939E19753DC5-8070
2 Faults Found:
000768 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - - MIL ON
Freeze Frame:
Fault Status: 11100001
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 167026 km
Time Indication: 0
Date: 2007.04.02
Time: 10:17:42
Freeze Frame:
RPM: 2844 /min
Load: 84.3 %
Speed: 65.0 km/h
Temperature: 94.0°C
Temperature: 18.0°C
Absolute Pres.: 990.0 mbar
Voltage: 14.351 V
000772 - Cylinder 4
P0304 - 001 - Misfire Detected - MIL ON
Freeze Frame:
Fault Status: 11100001
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 167026 km
Time Indication: 0
Date: 2007.04.02
Time: 10:17:42
Freeze Frame:
RPM: 2844 /min
Load: 84.3 %
Speed: 65.0 km/h
Temperature: 94.0°C
Temperature: 18.0°C
Absolute Pres.: 990.0 mbar
Voltage: 14.351 V
Readiness: 0010 1101VCDS
Self-Diagnosis Log
Monday,22,March,2021,21:01:11:02327
Page 3

------------------------------------------------------------------------------- Address 02: Auto Trans Labels: 09L-927-760.lbl
Part No SW: 4F5 910 156 A HW: 09L 927 156 C
Component: AG6 09L 4,2 FSI USA 0010
Revision: --H03--- Serial number: 4339229
Coding: 0000002

Your help is greatly appreciated. Thanks in advance.

[jbain2]

Maybe I missed it, but is there a reason you haven’t addressed the issue with the O2 sensor?


Sent from my iPhone using Audizine

[Formula76]

I was told that was not the issue, also I do not consistently get that fault code. The report I ran last night did not have it come up. Can you speak to me more directly about it? I more often get misfires than the actual 02 fault code. Any feedback on this given what I have just provided?

[Klaus Von R.]

Compression, fuel, spark

Have you compression tested your cylinders? Have you check you fuel injectors, have you checked your coil packs? Have you checked timing valves? Have you done a carbon cleaning? Do you have the proper fuel pressure?

These are all things you should look at.

[Formula76]

I replaced my high pressure fuel pump I didn't need to replace the other one my cam followers and everything we're good so I just needed the high pressure fuel pump on the passenger side I also did leak down testing about a year ago and that was fine compression read totally fine as well and I have checked all my coil packs and gone through those as well I had to replace one unless another one is all of a sudden gone.

I haven't had any fuel pressure issues or anything since I replaced my high pressure fuel pump so I think I handled all that.

About a year ago I had to pull my intake off and I cleaned out all of my flaps and did all of my carbon cleaning so I did all of that and completely cleaned out the top end of my motor so I don't think I have any of the carbon issues or anything in the flaps or in the intake areas so all that has been done as well.

[wavemaster]

Replace the O2 sensor, not very expensive and you can do it yourself.

Maybe....

[Formula76]

I ran the report again today and all I got was a misfire on cylinder #4. No 02 fault or anything. I guess I can go back to musical chairs with coil packs...

[Formula76]

Alright, so appreciate anyone who is still paying attention, I took some time today and ran over a dozen reports and tried as much testing as I could without really tearing it apart yet.

I literally test drove and ran 15 reports today with 98% showing misfires on Cylinder $4 no matter if 2, 3, or 4 coils were in cylinder #4.
The car can run really rough at times even though it appears to be just this one cylinder as the primary culprit.
Pretty much any musical chairs with coil packs. It is consistently faulting on cylinder #4.
The check engine light is just a chronic little lantern at this point. Its always on or comes right back on after clearing codes, etc.

#1 coil pack stayed in the same position during testing, and since I had replaced that one last year I wasn't too concerned about it. . No more misfires on cylinder #7 anymore and no more intermittent 02 fault codes. All I experienced is what I detailed above. I would love solid feedback on what I could look into next since this is the main drivability fault from what I can see and feel as of now.

Please see the report engine fault codes below:

Address 01: Engine Labels:. 079-907-560-BVJ.clb
Part No SW: 4F1 910 560 E HW: 4F1 907 560
Component: 4.2l V8/4V 0010
Revision: 74H04--- Serial number:
Coding: 01050009190F0120
Shop #: WSC 02335 758 00200
VCID: 2517F2E939E19753DC5-8070

2 Faults Found:
000768 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 -
Freeze Frame:
Fault Status: 01100001
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 167056 km
Time Indication: 0
Date: 2021.03.26
Time: 23:59:59
Freeze Frame:
RPM: 654 /min
Load: 30.2 %
Speed: 0.0 km/h
Temperature: 68.0°C
Temperature: 45.0°C
Absolute Pres.: 1020.0 mbar
Voltage: 13.716 V

000772 - Cylinder 4
P0304 - 001 - Misfire Detected
Freeze Frame:
Fault Status: 01100001
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 167056 km
Time Indication: 0
Date: 2021.03.26
Time: 23:59:59
Freeze Frame:
RPM: 654 /min
Load: 30.2 %
Speed: 0.0 km/h
Temperature: 68.0°C
Temperature: 45.0°C
Absolute Pres.: 1020.0


Anyone who wants more reporting data or is willing to weigh in on this and lend a helping pixilated hand so my next efforts are spent more effectively? I really do mean the three words following this...thanks in advance.

[wavemaster]

I noticed that these last two were at idle.

Looks like you may have multiple issues, intermittently

https://www.fcpeuro.com/Audi-parts/A...v=&keywords=o2

Don't know if that is the right year, but for less than $200 you will know if you made any change at all.