Anyone in PDX with 3.0 knowledge?

[Shagy30]

I have been trying to track down a random misfire on my 05 A4 3.0. It seems like I have tried just about everything.
It looks like all signs point to a head issue. Not sure if the was overheated or not. Didnt get that info from the previous owner.
Maybe I missed something. Anyone care to chime in?

Here are the symptoms:

Car misfires on cold start for a few seconds then evens out and runs great. Has good power and does not misfire on high RPMs.
Only misfires on cold start. After that if I shut it off and start it again it does not misfire.

What I have done so far.

Replaced MAF, Fuel Filter, Spark plugs, Coil packs, Vacuum hoses
Checked for Vacuum leaks, checked PCV Valve and breather hoses and Intake runner

Why i think its a head issue is because there is a significant amount of bubbles in the coolant reservoir when the cap is open.
Also the tailpipes get moist and after a while start to drip water.

Does anyone know this car? Maybe know the history?

Here are a couple quick pics

[PwrWgn]

Any more information you can share?

Scan the car for codes? Is the misfire being recognized by the car? With a vagcom you can look at misfire count for each cylinder independently. It's an extremely helpful diagnosis tool.

The symptoms you have could point to a zillion different things unless you work harder to narrow it down. I wouldn't be so suspicious of the head unless you knowingly drove around with it overheating.

Water is a byproduct of combustion. Condensation in your exhaust pipes is completely normal.

[Shagy30]

Only codes that come up are a random misfire and misfire on all 6 cylinders. There is also a code for the brake switch but thats unrelated.
If the misfire is bad enough it will throw the check engine light. Otherwise it doesnt recognize that it is misfiring. It all depends on how long the car has been sitting. The longer it sits the worse the misfire is on cold start.
The car doesnt overheat. the arrow sits dead center.

[Kruat]

Carbon buildup can cause cold start misfires, although not sure if 3.0s had carbon issues.

[PwrWgn]

Wish I could tell ya more, but it's not easy to do an armchair diagnosis. Since it misfires on all 6, it's really hard to point to something side- or cylinder-specific like a damaged head or valve.

ME7 should have a very specific cold-start routine: injection timing, ignition advance, throttle position. However, it should still take into account things like air & coolant temp. Consider checking these sensors out...you can perform a sanity check on these using vagcom measuring blocks (should be approx. equal to outside air temp after sitting overnight).

^^^ Also, if there is carbon buildup, maybe feed er a can of good ol' seafoam.

Good luck!

[V70R]

If you are still having problems, Send me a PM and I'll give you my phone number....I am fairly knowledgable with the AVK/B6 3L motors. Oh, and in Portland too!

[jeremy@matrix]

How many miles on the car? Records of maintenance history?

[Noggybowl]

There are some of the AVKs that have a block separation issue. When cooling off the cylinder liner separates from the aluminum block, leaking a little bit of coolant into the cylinder. When it warms up the leak heals up. I have seen it the most on cylinders 2 and 5. You can pull the plugs and see if you can use a boroscope to check for coolant after cool down.