# 30v V6 issue. Ignition related?



## 29er (Feb 25, 2007)

I apologize in advance for the lack of EXACT info, as I am simply going by what I was told.
A friend of mine has a 99 A4 with the 30v V6, tiptronic, approx 100k miles, maybe a little more.
She says that once every few weeks, the car will "vibrate and shudder" under acceleration, and the CEL will come on. After it stops, the CEL will stay on for 1-2 weeks and then go off. It will not come back until the issue returns.
I should note that the car is not driven very often at the moment due to school reasons, but when it is on weekends, it makes fairly long (near 2 hour) trips.
I am unaware of the maintenance records of the car, nor have I ever seen/heard it run, or even looked under the hood. I am unaware of any ECU codes, and I will be trying to borrow a code scanner soon to check it out.
I am assuming something ignition related. Any input?


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## Slimjimmn (Apr 8, 2006)

*Re: 30v V6 issue. Ignition related? (vrDUCKin)*

have to scan it when the check engine light is on, when it goes away after 2 weeks it is clearing itsself. 
Also I would just do plugs and wires and fuel filter.


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## 29er (Feb 25, 2007)

*FV-QR*

Yeah, scanning it is one of my priorities. It happened just this saturday, and the car was driven again and then parked sunday, so Im hoping it will store it until I get a chance to scan it which will probably not be at least until late this week. The car will probably not be driven between now and then.
My obvious assumption is either the coilpack or plug wires. Since it happens under acceleration, when the ignition system is under the most load it typically sees (this car isnt "beat on" at all). Would testing the wires and coilpack with a spray bottle with water be a good course of action?
Im not familiar with the 30v coilpack. Is it anything like the 12v VR6 coilpack, that can only be replaced as a unit? Or can parts be replaced. Does it have that same tendency to crack? If it is cracked, is a JB weld fix a viable temporary option?


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## spitpilot (Feb 14, 2000)

*Re: FV-QR (vrDUCKin)*

If the plug wires are 100K miles old..I'd just replace em...Amazon had set of Bosch lifetime silicone wires for $110 or so a few months back...lowest price I'd seen for good quality wire set...I installed one on my Passat and "stumbling" when opening throttle on the freeway went away. What you describe is typical misfire..car stumbles, CEL comes on...code either random misfire or cylinder specific if only one plug/wire is suspect will be stored...if misfires don't happen again for a few "start up/warm up cycles"..then CEL goes out..but codes remain until scanned and erased with a scan tool. http://****************.com/smile/emthup.gif


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## 29er (Feb 25, 2007)

*FV-QR*

Okay thanks, I think the car has only had a handful (under 5, probably under 3) start/stop cycles since the last misfiring incident. So it shouldnt be a problem.


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## MEDEL514 (Jan 12, 2002)

*Re: 30v V6 issue. Ignition related? (vrDUCKin)*

I think I'm having the same problem with my car. It hesitates under acceleration around 1000 to 1500 rpms, but runs smooth at anything after that, even at WOT in any gear. I'm thinking about buying some new NGK copper plugs and replacing the Bosch platinums that are in there. Hopefully that will fix it so I don't have to replace the coil pack.


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## spitpilot (Feb 14, 2000)

*Re: 30v V6 issue. Ignition related? (MEDEL514)*

I'd only run the BKR6EKUB NGK plugs specified! http://****************.com/smile/emthup.gif


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## MEDEL514 (Jan 12, 2002)

*Re: 30v V6 issue. Ignition related? (MEDEL514)*


_Quote, originally posted by *MEDEL514* »_I think I'm having the same problem with my car. It hesitates under acceleration around 1000 to 1500 rpms, but runs smooth at anything after that, even at WOT in any gear. I'm thinking about buying some new NGK copper plugs and replacing the Bosch platinums that are in there. Hopefully that will fix it so I don't have to replace the coil pack.

Sorry to thread jack!







But I just swapped in another set of spark plugs into the car just to see if the probelm would go away, but I'm getting the exact same results, Studdering at low RPM's during acceleration in any gear. 
Is there anyway to test the coil pack itself just to make sure that its ok? If I can rule out the coilpack as the problem then I'll buy a new set of wires. I'd just really hate to buy a set of expencive wire jsut to find out that the costly coil pack need to be changed as well.


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## 29er (Feb 25, 2007)

*FV-QR*

So I finally scanned it today. Got a P0304 code, which is a misfire for cylinder 4.
Also, she told me that it only happens when its raining, or it has just rained, and there will be water still in the engine bay.
So since it is only once cylinder (at least according to the code), would I be correct to assume that it is probably a plug wire for that cylinder? Since the coilpack is in groups of 2, I would assume that that the misfire would occur at the other cylinder that #4 is paired with as well.
The ross tech wiki also pointed to other possible causes such as an injector issue or an evap issue, but based on the other info I am doubting either of those.
If anyone has any insight, or can tell me which cylinder is #4, that would be much appreciated.


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