I'm at the dealer now. I've been getting a 2B64 error code and terrible idle quality. They could find no leaks (which is good, I've been looking for them for a couple weeks now...) and then checked the cam timing. They found that it could be positioned to be good but it was not at first and said that the VANOS unit was bad. They said that this often times causes a 2B64 code, "unmetered air in the intake manifold".
Does that make sense? I could see that causing a problem but I thought there were other codes for it the cam isn't phased how the ECM is expecting to find it. Mostly just thought it was weird that the only code I've been getting is 2B64.
Prior to bringing it in, the only thing I could think would be wrong is a throttle not fully closing. I'll let you know if it works...

 

Got the same code. I have a slight stumble at idle and I will eventually pull this code. I have no idea what is causing it but I did replace the VCG and it did not solve the problem. Please give us updates if you learn anything new. Thanks. The 2B64 is identified as "suction tube" How does that relate to the VANOS position? I guess it's time to research.

 

The only way I could see it relating is if the intake valve got held open too far into the compression stroke. Normally, on all but the mildest of cam grinds, the intake valve doesn't close until the compression stroke has started--just a little. If the intake valve stays open too long during that stroke, some of the air that has been drawn into the combustion chamber could go back out of the valve ("flow reversion") and be detected as un-metered air in the intake. Vanessa can change when the valve closes, so just maybe if it is wrong by the "right" amount?

That's the only possible connection I could see between VANOS and a perceived intake leak.

 

Slave to felines, I 100% agree with you. I would assume that the intake cam was very badly retarded and is doing exactly what you said. Even a tiny cam is going to have well over 180 degrees of duration, so some reversion is normal but mine must have been really bad. Oddly, my cranking compression was quite high, 220~240psi across all cylinders. Maybe it was just the solenoid that was bad and it would always fully advance the cam? It would usually start fine but then go bad after a few seconds of idle. Heck, I don't know and at the moment, I don't really care! They replaced the VANOS and solenoid and my months long headache has finally gone away! The blasted thing runs great!

Timski, mine was barely driveable the idle was so bad. My manifold pressure was only 3 in-Hg at idle! 2B64 is unmetered air in the intake manifold, so basically a leak (which mine was not...). Check all the connections (PCV, fuel tank breather, runners and throttle body is about it). If you can't find a leak, I've heard of people having bad welds in the manifold or a leaking PCV (valve cover) cause it. The VANOS solenoid is only about $120 and can be replaced with little more than removing the intake manifold to get to it, maybe try it? Look for leaks first, it is time consuming but free, unless you bring it somewhere to get smoke tested. Is that the ONLY code you're getting? How many miles do you have? I have almost 140K. You/we will get it fixed

It's been such a good day. I burned an exhaust valve at Thanksgiving, did some mild port work and rebuilt the head, and finally got everything back over a month ago but have been chasing this problem since then! Celebratory beer is being had!

 

800 miles and 2B64 didn't return.
Changed the VCG. So far so good.