# Random cylinder misfires, can't seem to solve it (VW Tiguan, 2.0L TSI)



## kagaku (Jan 17, 2013)

I've got a 2009 Tiguan with 65k miles on it. A few weeks ago I noticed some issues with running rough during a cold start. I only noticed because the engine would vibrate considerably more than usually for the first few minutes of operation, and would idle at around 1050-1100rpm instead of the usual 750rpm. After warm up, things were fine. Suddenly the issue got bad real fast - wife was out and the MIL light came on, EPC light came on, and the car was running extremely rough. We managed to drive it home (2 miles) doing under 20 the whole time on side streets. Once I hooked it up to my OBD reader, I was seeing cylinder misfire codes on all four cylinders.. P0300, P0301..P0304, all five codes simultaneously. 

Since the car was due for an oil change and hit 65k miles recently, I decided to throw new plugs in there to see if that would help. It did, at first.. A day or two it ran completely fine, no rough starts, no misfires, I thought I had solved the problem. The old plugs had some deposits on them and were original, so I thought I was in the clear. Two days later, same thing happened again.. EPC light, barely running and misfires on all four cylinders.. 

I read up some online and decided to order new ignition coils. Took a few days, but I got four new coils and threw them in. Again, problem solved it seemed. No more EPC light, misfire codes didn't come back and no more rough starts. I drove a good 40 miles with no problems at various speeds, but started noticing some misfires during acceleration (slightly rough acceleration, almost feels like a back and forth rocking motion, very slight). Sure enough, after a cold start I'm seeing the engine run a bit rough again with misfires. This time, only P0304 (misfire on cylinder 4) is thrown, and it only shows up as a "pending code" (engine light flashes for a few moments during start, but does not stay on). 

I checked my connections, swapped the plugs and coils in what I thought were cylinders 3 and 4 (closer to the driver side), nothing. I swapped what I think are cylinder 1 and 2 (passenger side) just to be sure, but still nothing. At this point I'm pretty lost. I know enough to be dangerous with a carbureted engine, but am lacking in knowledge when it comes to a fuel injected turbo charged VW engine.  It seems to be cylinder 4 misfiring consistently at this point according to the OBD reader. 

Also of note.. I had some misfire problems last year, and had my intake manifold replaced as part of a recall (also had carbon deposits removed at the same time). Can a carbon build up occur this fast? Can it be the injectors?


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## alexsautohaus (Jun 14, 2013)

Have you checked for any vacuum leaks after the MAF? Do you have vag-com? What is your long term and short term fuel trim? There isn't quite enough information in your post to tell if your misfires are ignition or fuel related.


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## Katiekat1979 (Feb 10, 2021)

Hello! I see this is from 2014 but it’s exactly what I have going on! I have a 2013 with about 130k. I have replaced my plugs, which helped some. Was going to order coils but thought I’d do some investigation first. My gas mileage is terrible and I’m diligent about using the recommended fuel. I have not checked for vacuum leaks. Frankly I’ll have to figure out how to do that. Any advice would be appreciated  thanks in advance!




alexsautohaus said:


> Have you checked for any vacuum leaks after the MAF? Do you have vag-com? What is your long term and short term fuel trim? There isn't quite enough information in your post to tell if your misfires are ignition or fuel related.


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## ROH ECHT (Dec 9, 2010)

It could be the MAF or a leak somewhere in the air inlet between the MAF and the inlet ports.You can unplug the MAF at idle. Generally it will stumble with a good MAF...but if no change, then the MAF is likely bad or it has a significant leak. This can also be checked with the right scan tool to view mass air data. 

You can do a visual to locate leaks, but it will take a thorough smoke test session to detect or rule out any leaks present.

Could be the PCV is failed...its valves and diaphragm are also known to fail.

It could be damaged brake booster tubing. The tubing is known to split and often does so on the under side. So feel for cracks where ever the brake booster is connected to fittings.

It could be buildup/fouled inlet valves...but you say those were cleaned recently. One could still quickly view their condition with an endo-scope through the IAT sensor port on the inlet manifold.

What plugs were swapped in? What were the confirmed gaps on them?


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## Katiekat1979 (Feb 10, 2021)

Hey! Thanks for getting back to me so quickly and for the lengthy list of things to check. I appreciate your time. 
I haven’t been able to check through much yet as it is super effing cold right now. But I’m hoping to dig in over the weekend. 
Turns out I also have oil on one of my coils. Valve cover gasket I’m guessing? Which is apparently a very involved job? Argh. 
Spark plugs are 0.032 I believe. Iridium but I can’t recall the brand at moment.
Thanks again!


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## nutsofast1.8T (Feb 4, 2004)

Check your injector connections. Any dirt, water, fuel, or corrosion on the connections will impede the signal. Or bad injector wire like the sheathing chaffed and is bare wire, short to ground. Or injector bad altogether.


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## ROH ECHT (Dec 9, 2010)

Katiekat1979 said:


> Hey! Thanks for getting back to me so quickly and for the lengthy list of things to check. I appreciate your time.
> I haven’t been able to check through much yet as it is super effing cold right now. But I’m hoping to dig in over the weekend.
> Turns out I also have oil on one of my coils. Valve cover gasket I’m guessing? Which is apparently a very involved job? Argh.
> Spark plugs are 0.032 I believe. Iridium but I can’t recall the brand at moment.
> Thanks again!


Valve cover seal is quite easy...the cam cradle much tougher because it must be well cleaned of its old sealant. 

If you do the valve cover seal...here is the tightening order and torque is 10 Nm/7 lb*ft. Also, be sure to use new bolts for the new bolt-seals on them (may end up a better deal to just replace the valve cover which comes with new bolts and the valve cover seal). Valve Cover Bolt - Priced Each


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## AutoTech73 (Feb 13, 2021)

I will advise, do not take anything apart just yet nor replace any part yet. Good you have OBD2 Scan tool. Let the car warm up and then plug it in. Don't forget to switch off ignition before doing that. Get the code out and note it down, then check the freeze frame, thereafter go to the live data. Pick the following pids: engine rpm, calculated load, engine Temp, MAF, IAT, short and long term trim for both banks if two. You post the data here and let's analyse and let's know if you should continue the ignition system check path or not.


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## AntonI76 (Feb 17, 2021)

Hey. Got check engine light going on and off, replaced ignition coils and sparkplugs on my 2015 tiguan and still misfires. Can feel the vibration on acceleration sometimes, happends mostly at the beggining of the trip, however lately noticed it takes longer to kind of warm up.


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## SJWilshire (Jan 3, 2022)

2018 just started this misfiring business on cyl 3
Wife made it home with an EPC light, got the scan tool on It got a P020300. Cleared the code, car ran as normal.
WD40'd everything.
Car fine, 2 days later (today) car misfires on the way to work. Pulled over, restarted and the car runs normally.
That screams data short or software to me - anyone had similar to that?


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## AC2hetzjr (12 mo ago)

SJWilshire said:


> 2018 just started this misfiring business on cyl 3
> Wife made it home with an EPC light, got the scan tool on It got a P020300. Cleared the code, car ran as normal.
> WD40'd everything.
> Car fine, 2 days later (today) car misfires on the way to work. Pulled over, restarted and the car runs normally.
> That screams data short or software to me - anyone had similar to that?


On 2018 and 2019 Volkswagen Tiguan 2.0L engine codes DDSA and DGUA if you are having intermittent miss fires on any cylinder DTC P0201, P0202, P0203, P0204. There is a tech tip issued by Volkswagen dated 2/21/2020 tech tip# 01-20-02TT transaction# 2058719/1 The T8 wiring harness to the fuel injectors needs to be replaced.


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## Dongwu (Jun 21, 2021)

My 2011 Tiguan got P0304, I have replaced all 4 coils but after 2 days, the engine light back and P0304 again.
Attached is the report generated by the Torque Pro app, please help me.
Mode $06 report generated by Torque for Android
================================================

Vehicle Manufacturer: Volkswagen


Test report:
------------------
MID:$01 TID:$83
- O2 Bank 1 Sensor 1
Max: 1.99882 Min: 0.30003
Test result value: 0.97136
PASS
----
MID:$01 TID:$84
- O2 Bank 1 Sensor 1
Test incomplete or dependant test failed
--
MID:$01 TID:$89
- O2 Bank 1 Sensor 1
Max: 1.99882 Min: 0.19993
Test result value: 0.96475
PASS
----
MID:$02 TID:$05
Rich to Lean sensor switch time(calculated) - O2 Bank 1 Sensor 2
Test incomplete or dependant test failed
--
MID:$02 TID:$81
- O2 Bank 1 Sensor 2
Test incomplete or dependant test failed
--
MID:$02 TID:$82
- O2 Bank 1 Sensor 2
Test incomplete or dependant test failed
--
MID:$02 TID:$8a
- O2 Bank 1 Sensor 2
Test incomplete or dependant test failed
--
MID:$21 TID:$84
- Catalyst Monitor Bank 1
Test incomplete or dependant test failed
--
MID:$35 TID:$80
- VVT Monitor Bank 1
Max: 28° Min: 20°
Test result value: 28°
PASS
----
MID:$35 TID:$81
- VVT Monitor Bank 1
Max: 28° Min: 20°
Test result value: 28°
PASS
----
MID:$3a TID:$81
- EVAP Monitor (0.090")
Test incomplete or dependant test failed
--
MID:$3b TID:$81
- EVAP Monitor (0.040")
Test incomplete or dependant test failed
--
MID:$3c TID:$81
- EVAP Monitor (0.020")
Test incomplete or dependant test failed
--
MID:$3c TID:$82
- EVAP Monitor (0.020")
Test incomplete or dependant test failed
--
MID:$3d TID:$80
- Purge Flow Monitor
Test incomplete or dependant test failed
--
MID:$3d TID:$88
- Purge Flow Monitor
Max: 65,535Count Min: 1Count
Test result value: 1Count
PASS
----
MID:$41 TID:$85
- O2 Heater Monitor Bank 1 - Sensor 1
Max: 6,553.5°C Min: 755°C
Test result value: 818.90002°C
PASS
----
MID:$42 TID:$81
- O2 Heater Monitor Bank 1 - Sensor 2
Test incomplete or dependant test failed
--
MID:$a2 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 1 Data
Max: 65,535 Min: 0
Test result value: 2
PASS
----
MID:$a2 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 1 Data
Max: 65,535 Min: 0
Test result value: 0
PASS
----
MID:$a3 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 2 Data
Max: 65,535 Min: 0
Test result value: 0
PASS
----
MID:$a3 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 2 Data
Max: 65,535 Min: 0
Test result value: 0
PASS
----
MID:$a4 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 3 Data
Max: 65,535 Min: 0
Test result value: 0
PASS
----
MID:$a4 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 3 Data
Max: 65,535 Min: 0
Test result value: 0
PASS
----
MID:$a5 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 4 Data
Max: 65,535 Min: 0
Test result value: 11
PASS
----
MID:$a5 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 4 Data
Max: 65,535 Min: 0
Test result value: 9
PASS


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## vwdoc1 (Jun 30, 2003)

Are these 2.0T engines still prone to carbon building up on the intake valves causing misfires. This carbon buildup on the valves can restrict airflow into the combustion chamber.





GDi Servicing: Don't let carbon build-up become a big issue | Delphi Auto Parts


No new technology is trouble free, and unfortunately GDi is no exception.




www.delphiautoparts.com




Not sure the following method works as I am used to hearing that manually cleaning off that debris works best. 

How do you clean carbon build up on a 2.0 TFSI engine?




*Driving the engine at just over 3000 RPM* raises the temperature and puts the engine into a “cleaning mode” where it runs leaner and hotter clearing out a lot of the carbon build up inside the engine, so try to hit this sweet spot as often as you can and for at least 15 minutes per week.


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