# Misfire on 1.8t cylinder #3



## VR6con92 (Jan 9, 2006)

I have a misfire on cylinder 3. I changed plugs, got the same thing. Switch coils around same thing. Only cylinder 3 would misfire. And the misfire got worse. Once the car warms up the misfire stops it's only on start up I'll get a bad misfire. I'm thinking it's the injector. What you guys think?


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## VR6con92 (Jan 9, 2006)

Bump anyone?


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## 87vr6 (Jan 17, 2002)

VR6con92 said:


> Once the car warms up the misfire stops it's only on start up I'll get a bad misfire. I'm thinking it's the injector. What you guys think?


Good start. You can swap injectors too, it wouldn't take much more than 30 minutes... I'm also thinking maybe crack wiring harness for the coil... Try the injector first.


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## VR6con92 (Jan 9, 2006)

87vr6 said:


> Good start. You can swap injectors too, it wouldn't take much more than 30 minutes... I'm also thinking maybe crack wiring harness for the coil... Try the injector first.


Harness is fine. I didn't swap injectors. I just got a set from a friend. With 30k on them. Mine has 60k. It went from a slight misfire to a really bad misfire now.


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## VR6con92 (Jan 9, 2006)

changed plugs,coils pack and i changed the injectors, i keep getting misfire on # 3. anyone know why or had this problem please help.....


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## rodgertherabit (Apr 16, 2009)

This actually happened to me today!  

if you got the code P0300 along with P0303 then you probably have a Vacuum leak. It will cause misfiring, running rich, and a bumpy idle.


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## VR6con92 (Jan 9, 2006)

rodgertherabit said:


> This actually happened to me today!
> 
> if you got the code P0300 along with P0303 then you probably have a Vacuum leak. It will cause misfiring, running rich, and a bumpy idle.


 It misfires bad on start up. Then it will go away. If I hook up the bag there is a very slight misfire. U wouldn't notice but I had the vag to it.


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## VR6con92 (Jan 9, 2006)

Did compression test and everything is fine. Could it be the coil pack harness maybe have a sharp age in it?


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## K20017 (Nov 14, 2007)

Are you getting any codes?


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## CC'ed (Dec 1, 2009)

I had a similar problem with my 2005 1.8T AWM. New plugs, coils, and ECT did not fix the problem. No vacuum leaks found.....it was a blown head gasket, which slowely leaked coolant into cyl #2, as the car sat overnight, causing a misfire which went away after about 10 sec, then the car ran fine, just slowly loosing coolant as it was driven.


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## VR6con92 (Jan 9, 2006)

CC'ed said:


> I had a similar problem with my 2005 1.8T AWM. New plugs, coils, and ECT did not fix the problem. No vacuum leaks found.....it was a blown head gasket, which slowely leaked coolant into cyl #2, as the car sat overnight, causing a misfire which went away after about 10 sec, then the car ran fine, just slowly loosing coolant as it was driven.


 I also loose coolant slowly. But sometimes the car starts fine sometimes it doesnt. Sametime is runs fine all day long. Then out of no where it would act up. I'm only getting p0303 code. But if you pull out the plug it would be drenched with gas.


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## 87vr6 (Jan 17, 2002)

If you pull a plug that's covered in gas, that means that cylinder isn't firing or the injector is pushing way too much. I still stand by a coil pack harness problem seeing as you changed all the other variables including the injectors, and the problem still exists.


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## radlynx (Jan 4, 2007)

get your engine oil tested. from there, you will know if coolant is mixing with the oil. then you know it's a head gasket.



VR6con92 said:


> I also loose coolant slowly. But sometimes the car starts fine sometimes it doesnt. Sametime is runs fine all day long. Then out of no where it would act up. I'm only getting p0303 code. But if you pull out the plug it would be drenched with gas.


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## jon-vw (May 25, 2011)

I second the notion for a cracked wiring harness. I'm dealing with the exact same problem myself. If you go this route, be sure to buy the Schwaben terminal kit.


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## VR6con92 (Jan 9, 2006)

jon-vw said:


> I second the notion for a cracked wiring harness. I'm dealing with the exact same problem myself. If you go this route, be sure to buy the Schwaben terminal kit.


so was it your wiring harness also ?


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## Slimjimmn (Apr 8, 2006)

pull the plug and see if the top of the piston is silver clean. If it is, then the HG is shot.


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## CC'ed (Dec 1, 2009)

A blown head gasket does not always leak coolant into the oil, or oil into the coolant. My head gasket was just leaking coolant into cylinder #2. My oil and coolant was not being cross contaminated.


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## VR6con92 (Jan 9, 2006)

Finally figured out the problem. It's a bad head gasket. Leaking coolant into cylinder #3


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## radlynx (Jan 4, 2007)

how did you figure it out? what tests did you make? 



VR6con92 said:


> Finally figured out the problem. It's a bad head gasket. Leaking coolant into cylinder #3


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## VR6con92 (Jan 9, 2006)

radlynx said:


> how did you figure it out? what tests did you make?


 Did the wireharness, start car up no misfire shown on vag. As soon as I add coolant misfire on #3 and oil was milky when I checked oil cap.


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## radlynx (Jan 4, 2007)

Great! thank you. well at least you now know what to do next.  



VR6con92 said:


> Did the wireharness, start car up no misfire shown on vag. As soon as I add coolant misfire on #3 and oil was milky when I checked oil cap.


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## VR6con92 (Jan 9, 2006)

The head got put marks by the water jackets. Metal is missing


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## Slimjimmn (Apr 8, 2006)

Slimjimmn said:


> pull the plug and see if the top of the piston is silver clean. If it is, then the HG is shot.


 good deal:wave:


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## vwbmx (Jan 25, 2002)

I know I am late on this but I have been having multiple cylinder misfires and leaking coolant and I have checked my coil packs and throttlebody. I changed the coilpack overlay harness and still issues so I am going to do a compression test and see where I am at. thanks


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