Random misfires

B7RS4, 103,000 miles.

current state: Misfires on 5,8,4,3, random/multiple misfire code P0768.

history:
my car has been running great for a long time. I bought it about 3 years ago. no issues. Good maintenance history. I went to piggie pipes about 12 months ago. It has continually been throwing codes for O2 sensors. Replaced a few, added spacers, still throwing codes. So, its coming time for me to get the thing an Echeck. I couldn’t get the O2 codes to go away, so I figured I’d just buy a set of used standard downpipes and toss them on and swap back after the car gets the OK. right before tossing on the downpipes on cold mornings I would notice the slightest hesitation when driving my daughter to school. didn’t notice it any other time. Only lasted for about 5 minutes and it would go away. no codes thrown. Figured it was just time for a carbon clean.

So, I had my local indy (~1 mile from my house) VW/Audi shop toss on the downpipes and after picking it up, it started having major random misfires. Almost undriveable. really bad. So, I opened her up for maintenance. I did plugs, coils, carbon clean, injector service - clean/seals (replaced one injector that the plastic was busted on), oil, filters (fuel, oil,cabin) - all the good stuff.

http://www.voidopolis.com/images/carbon-01.jpg

http://www.voidopolis.com/images/cleaned.jpg

After getting everything put back together, I’m still seeing the misfire problems. not anywhere near as bad as it was before, but still there. If I reset the codes, it runs somewhat normally and then goes back into a misfire condition. it seems to cycle through running rough and running semi-OK.

I’ve done some logging. I was reading in another thread about logging 003/103/106 to check the fuel system. I’ve included the details below from a scan and some data.

My assumption is that the downpipes that I bought are bad or plugged or something. my next step is to swap them back on to see if that changes anything. but I thought Id check with you guys to see if there is something else I should be looking at.

Monday,12,June,2017,19:04:14:39744
VCDS Version: 17.1.3.0 (x64)

VIN: License Plate: RS4-1

Mode 07: Pending emission related fault codes

Address 7E8: No fault code found.

Address 7EA: 5 Faults Found:
P0300 - Random/Multiple Cylinder Misfire Detected
P0305 - Cylinder 5: Misfire Detected
P0308 - Cylinder 8: Misfire Detected
P0304 - Cylinder 4: Misfire Detected
P0303 - Cylinder 3: Misfire Detected



Chassis Type: 8E (8E - Audi A4/S4/RS4 B6/B7 (2001 > 2008))
Scan: 01 02 03 08 09 0F 11 15 16 17 18 25 36 37 45 46 55 56 57 65
67 69 75 76 77

VIN: WUARU78E87N905669 Mileage: 167160km-103868miles

Address 01: Engine Labels: 079-910-560-BNS1.lbl
Part No SW: 8E1 910 560 A HW: 8E1 907 560
Component: 4.2L V8/4V FSI ª0060
Revision: 57H15— Serial number: XXXXXXXXXXXXXX
Coding: 01040009180F0160
Shop #: WSC 08252 444 57643
VCID: 244037D2E740BF61AD-8070

1 Fault Found:
006435 - Please Check DTC Memory of ECU Number 2
P1923 - 008 -
Freeze Frame:
Fault Status: 01101000
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 167159 km
Time Indication: 0

         Freeze Frame:
                RPM: 3800 /min
                Load: 17.6 %
                Speed: 74.0 km/h
                Temperature: 97.0°C
                Temperature: 44.0°C
                Absolute Pres.: 980.0 mbar
                Voltage: 13.589 V

Readiness: 0110 1101


Address 03: ABS Brakes Labels: 8E0-910-517.clb
Part No SW: 8E0 910 517 G HW: 8E0 614 517 BD
Component: ESP8 quattro H06 0150
Revision: 00000000 Serial number: 00000000000000
Coding: 0004533
Shop #: WSC 06335 000 00000
VCID: 2B52DCEE8A9E70196C-807E

1 Fault Found:
01826 - Sensor for Steering Angle (G85); Supply Voltage Terminal 30
000 - - - Intermittent
Freeze Frame:
Fault Status: 00100000
Fault Priority: 3
Fault Frequency: 15
Reset counter: 40
Time Indication: 0

         Freeze Frame:
                Hex Value: 0x0000
                Hex Value: 0x4222
                Hex Value: 0x0024
                Hex Value: 0x0197
                Hex Value: 0x0001

Address 08: Auto HVAC Labels: 8E0-820-043.lbl
Part No: 8E0 820 043 BM
Component: A4 Klimaautomat 3233
Coding: 00000
Shop #: WSC 00000
VCID: 6DD612F6270ABE2932-50E6

1 Fault Found:
01206 - Signal for Duration of Ignition Off Time
27-00 - Implausible Signal


Address 09: Cent. Elect. Labels: 8E0-907-279-8EC.lbl
Part No: 8E0 907 279 N
Component: int. Lastmodul ECE 0907
Coding: 01031
Shop #: WSC 65536
VCID: 3D76E2B637EAEEA9C2-4A3A

No fault code found.


Address 11: Engine II Labels: 079-910-560-BNS2.lbl
Part No SW: 8E1 910 560 A HW: 8E1 907 560
Component: 4.2L V8/4V FSI ª0060
Revision: 57H15— Serial number: XXXXXXXXXXXXXX
Coding: 01040009180F0160
Shop #: WSC 08252 444 57643
VCID: 244037D2E740BF61AD-8070

5 Faults Found:
000768 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 -
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 167159 km
Time Indication: 0

         Freeze Frame:
                RPM: 3737 /min
                Load: 63.1 %
                Speed: 73.0 km/h
                Temperature: 97.0°C
                Temperature: 44.0°C
                Absolute Pres.: 980.0 mbar
                Voltage: 13.462 V

000773 - Cylinder 5
P0305 - 001 - Misfire Detected
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 167159 km
Time Indication: 0

000776 - Cylinder 8
P0308 - 001 - Misfire Detected
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 167159 km
Time Indication: 0

         Freeze Frame:
                RPM: 3737 /min
                Load: 63.1 %
                Speed: 73.0 km/h
                Temperature: 97.0°C
                Temperature: 44.0°C
                Absolute Pres.: 980.0 mbar
                Voltage: 13.462 V

000772 - Cylinder 4
P0304 - 001 - Misfire Detected
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 167159 km
Time Indication: 0

000771 - Cylinder 3
P0303 - 001 - Misfire Detected
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 167161 km
Time Indication: 0

         Freeze Frame:
                RPM: 746 /min
                Load: 44.7 %
                Speed: 3.0 km/h
                Temperature: 96.0°C
                Temperature: 45.0°C
                Absolute Pres.: 990.0 mbar
                Voltage: 13.335 V

Address 15: Airbags Labels: 8E0-959-655-94.lbl
Part No SW: 8E0 959 655 H HW: 8E0 959 655 H
Component: Airbag 9.41 H12 3840
Revision: 91H12384 Serial number: 0036N0G0R0F4
Coding: 0432607
Shop #: WSC 06335 000 00000
VCID: 3C70EFB27FF0E7A1F5-8068

Subsystem 1 - Part No: 8E0 910 339 B
Component: BF-Gewichtsens. 002 0070

Subsystem 2 - Serial number: 3HLKX

Subsystem 3 - Serial number: 0001.01.000000200000000000ÿ†63

Subsystem 4 - Serial number: 000000ÿ†6332DRB4047A4DA8$ÿ†63

Subsystem 5 - Serial number: A4DA8$ÿ†6342DRB4047B0E2E-ÿ†63

Subsystem 6 - Serial number: B0E2E-ÿ†6352ARB401EC90A4Wÿ†63

Subsystem 7 - Serial number: C90A4Wÿ†6362ARB401E90B6AYÿ†63

Subsystem 8 - Serial number: 90B6AYÿ†63729RB401EF80D5$ÿ†63

Subsystem 9 - Serial number: F80D5$ÿ†63829RB401EF80A2Yÿ

Subsystem 10 - Serial number: F80A2Yÿ

No fault code found.


Address 16: Steering wheel Labels: 8E0-953-549-T.lbl
Part No: 8E0 953 549 T
Component: Lenksáulenmodul 0301
Coding: 04441
Shop #: WSC 06335
VCID: 4480975254009F618D-4A3A

2 Faults Found:
01301 - Control Module for Voice Recognition (J507)
49-00 - No Communications
01303 - Telephone Transceiver (R36)
49-00 - No Communications


Address 17: Instruments Labels: 8E0-920-9xx-8EC.lbl
Part No SW: 8E0 920 982 R HW: 8E0 920 982 R
Component: KOMBI+WFS 4 H14 0100
Revision: 0100 Serial number: 00000000000000
Coding: 0023268
Shop #: WSC 03131 444 12345
VCID: 3D76E2B667EAEEA9C2-5072

1 Fault Found:
01303 - Telephone Transceiver (R36)
004 - No Signal/Communication


Address 25: Immobilizer Labels: 8E0-920-9xx-8EC.lbl
Part No SW: 8E0 920 982 R HW: 8E0 920 982 R
Component: KOMBI+WFS 4 H14 0100
Revision: 0100 Serial number: 00000000000000
Coding: 0023268
Shop #: WSC 03131 444 12345
VCID: 3D76E2B667EAEEA9C2-5072

1 Fault Found:
01303 - Telephone Transceiver (R36)
004 - No Signal/Communication


Address 46: Central Conv. Labels: 8E0-959-433-MAX.clb
Part No: 8E0 959 433 CG
Component: Komfortgerát T7B 4135
Coding: 11820
Shop #: WSC 06335
VCID: 78F833A258480B81D1-4A3A

Subsystem 1 - Part No: 8E1959801G
Component: Tõrsteuer.FS BRM 0706

Subsystem 2 - Part No: 8E1959802G
Component: Tõrsteuer.BF BRM 0706

Subsystem 3 - Part No: 8E0959801E
Component: Tõrsteuer.HL BRM 0606

Subsystem 4 - Part No: 8E0959802E
Component: Tõrsteuer.HR BRM 0606

2 Faults Found:
00955 - Key 1
35-10 - - - Intermittent
00956 - Key 2
35-10 - - - Intermittent


Address 55: Headlight Range Labels: 4F0-910-357.lbl
Part No SW: 4F0 910 357 F HW: 4F0 907 357 F
Component: AFS 1 H01 0020
Revision: 00000001 Serial number:
Coding: 0000019
Shop #: WSC 06335 000 00000
VCID: 295E26E6806262099E-807C

Subsystem 1 - Part No: 8E0 941 329 A
Component: AFS-Modul links H04 0020

Subsystem 2 - Part No: 8E0 941 329 A
Component: AFS-Modul rechtsH04 0020

No fault code found.

End-------------------------(Elapsed Time: 06:57)--------------------------



            Address 01: Engine  (8E1 910 560 A)

19:18:17 Group 003: General
760 /min Engine Speed (G28)
3.50 g/s Mass Air Flow (G70)
2.7 % Throttle Valve Angle
10.5 °BTDC Ignition Timing Angle

19:18:17 Group 103: Fuel Injection (Fuel Pump Adaptation)
6.39 bar Current Fuel Pressure
-301 Fuel Pressure Regulator
121 Adaptation Value elect. Fuel Pump
Test OFF Fuel Pump Adapt. Status

19:18:17 Group 106: Fuel Injection (Fuel Pressure)
21.45 bar Fuel Rail Pressure
ON Electrical Fuel Pump

276.00 s Shut-Off Time



            Address 01: Engine  (8E1 910 560 A)

19:18:18 Group 003: General
760 /min Engine Speed (G28)
3.50 g/s Mass Air Flow (G70)
2.7 % Throttle Valve Angle
11.3 °BTDC Ignition Timing Angle

19:18:18 Group 103: Fuel Injection (Fuel Pump Adaptation)
6.46 bar Current Fuel Pressure
-336 Fuel Pressure Regulator
121 Adaptation Value elect. Fuel Pump
Test OFF Fuel Pump Adapt. Status

19:18:18 Group 106: Fuel Injection (Fuel Pressure)
21.27 bar Fuel Rail Pressure
ON Electrical Fuel Pump

276.00 s Shut-Off Time



            Address 01: Engine  (8E1 910 560 A)

19:19:06 Group 003: General
760 /min Engine Speed (G28)
3.69 g/s Mass Air Flow (G70)
3.1 % Throttle Valve Angle
7.5 °BTDC Ignition Timing Angle

19:19:06 Group 103: Fuel Injection (Fuel Pump Adaptation)
6.60 bar Current Fuel Pressure
-321 Fuel Pressure Regulator
121 Adaptation Value elect. Fuel Pump
Test OFF Fuel Pump Adapt. Status

19:19:06 Group 106: Fuel Injection (Fuel Pressure)
21.61 bar Fuel Rail Pressure
ON Electrical Fuel Pump

276.00 s Shut-Off Time



            Address 01: Engine  (8E1 910 560 A)

19:19:44 Group 003: General
760 /min Engine Speed (G28)
3.75 g/s Mass Air Flow (G70)
3.1 % Throttle Valve Angle
3.8 °BTDC Ignition Timing Angle

19:19:44 Group 103: Fuel Injection (Fuel Pump Adaptation)
6.40 bar Current Fuel Pressure
-314 Fuel Pressure Regulator
121 Adaptation Value elect. Fuel Pump
Test OFF Fuel Pump Adapt. Status

19:19:44 Group 106: Fuel Injection (Fuel Pressure)
21.92 bar Fuel Rail Pressure
ON Electrical Fuel Pump

276.00 s Shut-Off Time



            Address 01: Engine  (8E1 910 560 A)

19:19:46 Group 003: General
760 /min Engine Speed (G28)
3.64 g/s Mass Air Flow (G70)
3.1 % Throttle Valve Angle
8.3 °BTDC Ignition Timing Angle

19:19:46 Group 103: Fuel Injection (Fuel Pump Adaptation)
6.47 bar Current Fuel Pressure
-299 Fuel Pressure Regulator
121 Adaptation Value elect. Fuel Pump
Test OFF Fuel Pump Adapt. Status

19:19:46 Group 106: Fuel Injection (Fuel Pressure)
21.73 bar Fuel Rail Pressure
ON Electrical Fuel Pump

276.00 s Shut-Off Time

when DPs fail the tend to start throwing misfire codes. Also its hard to peg down as pre cats hold the car back a little bit but if you feel like the car is struggling to make it smoothly through the rev range that is another sign that the DPs might be bad

Consider the JHM tune it helps keep the CEL away for no Precat.

Wellp. the shop figured out what the issue was. The O2 sensors were swapped front to back…

Now the car is running like a dream. no hesitation, no misfire. The kick is there. I have not done the 3rd gear pull yet, but you can tell she is glad all the maintenance is complete. Thanks for the support. I’m so happy this forum exists to deliver sound advise! cheers!

WOW that is one you don’t hear of that often. STill its good that you updated the thread. Its good to know that swapped 02s can cause all these issues.