# Tried it all. V6 misfire.



## G-rocco (Sep 11, 2004)

I've been having a lot of trouble with my B5 since I got it this spring.
It throws a CEl and runs roughly, but it was at least drivable for a while - then the light would go out and it would fire on all cylinders.
Then it got much worse, only firing on 1 cyl! Obviously, it's un drivable.
This is the first thread I made about it:

http://www.passatworld.com/for...il+v6
I've run 6 things of techron through it. I've pulled the fuel rail and measured fuel output and checked spray pattern. Looked good.
I've replaced the spark plugs, the old ones were fouled. I've checked the coil; 2ndary resistance (which is all Bently instructs to measure) is good. I've checked the plug wires, the resistance is WNL. 
I've sprayed everything with water, to check for spark leaks. Nothing.
VAG-Com sort of points to the MAF. It's had the flow straightener removed, and while at idle it's flowing 9g/s air; spec is 3 to 5.
If I unplug the MAF while the car is running, it either starts to idle high and then stalls, or doesn't really change at all. 
Other thoughts?


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## spitpilot (Feb 14, 2000)

*Re: Tried it all. V6 misfire. (G-rocco)*

Plug wires can measure in spec and still be a problem...the metal contacts can lose their spring pressure over time and you'll get weak spark..happened to me once..drove me nuts since I had replaced/checked everything just as you have, but car still stumbled..at some RPM range...pulled wires off to check plugs once again..and noticed little black arc marks on one plug terminal...contact was poor and spark was jumpin at the wire/plug contact instead of inside the motor!...got new wire set..all was well! Just a thought..good luck! http://****************.com/smile/emthup.gif


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## chudzikb (Sep 21, 2000)

*Re: Tried it all. V6 misfire. (spitpilot)*

+1 on the wires, known problem, if not now, in the future, just change and never look back...


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## Slimjimmn (Apr 8, 2006)

*Re: Tried it all. V6 misfire. (chudzikb)*

Install a new maf sensor with the screen in it. VW puts it there for a reason, to properly route the airflow through the sensor. Without the screen the airflow wont correctly be measured.


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## VT 4-motion (Jun 14, 2009)

Change the plug wires. I checked the resistance on my wires, they all were within specs when pulled out and bent upward. When bent down, there was a short in one of them. I have to thank Spitpilot for this one. NAPA sell NGK wires for about $140. I'm sure the lack MAF screen could also be an issue.


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## spitpilot (Feb 14, 2000)

*Re: (VT 4-motion)*


_Quote, originally posted by *VT 4-motion* »_Change the plug wires. I checked the resistance on my wires, they all were within specs when pulled out and bent upward. When bent down, there was a short in one of them. I have to thank Spitpilot for this one. NAPA sell NGK wires for about $140. I'm sure the lack MAF screen could also be an issue.
 Amazon had special on Bosch lifetime warranty silicone wire set for V6 @ $110 delivered when I bought one a month or two ago...check that out..I've run Bosch wires for years 'n years with no complaints!


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## G-rocco (Sep 11, 2004)

New MAF, new plug wires, new plugs. No change. http://****************.com/smile/emthdown.gif


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## newtome (Aug 1, 2009)

*Re: (G-rocco)*

Replace the vacum lines, should be pretty cheap. I have regular rubber hoses. Here's my thread; http://forums.vwvortex.com/zerothread?id=4503029 I haven't gotten to cleaning the throttle body but I'm willing to bet it'll work. Mine too has started to run well again and the light went out. I'm still going to clean it as soon as I can.


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## Slimjimmn (Apr 8, 2006)

*Re: (G-rocco)*

what codes are you getting? is it only a cyl 1 misfire?
you try swappingthe #1 and #2 injector see if it changes.


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## G-rocco (Sep 11, 2004)

I replaced the coil. A friend was reviewing the codes and pointed out that there were two coil power output malfunction codes that I had ignored. it was then confirmed that meant the coil was toast.
found it for $75 from FCP groton (?) and replaced it, good as new. http://****************.com/smile/emthup.gif


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