One might utilize a dyno to fine tune the engine with IMT - Intake manifold tuning.
Otherwise - only your wallet will have a difference.

One could look at:
http://www.pvv.org/~shane/stasj/pics...g%20system.pdf

 

A Dyno?

His crossover is completely inoperable.

 

A crossover?

He has an A6.

 

Thank you everyone for your help and input. The posted photos were really helpful, too. Here's what I've pieced together. I had a disconnected vac line (one of the connectors had snapped in two). I replaced that. I think I could stand to replace all the vac lines, but I didn't see any other blatant leaks. The two manifold arms are stuck in place, but they aren't stuck in the "open" position like I thought. The photos posted in this thread earlier helped me to determine that. I think I must have been thinking about the spring backwards.

As described earlier, the driver's side linkage arm is no more - it's not even there. From my understanding and from the videos of the whole deal in action, it appears that both valves are supposed to be inflated when the engine is off, pushing those manifold arms against their springs. When you turn the engine on, both valves should be "sucked" in, letting the manifold arms go back to rest. I've turned on the A6, let it idle for about five minutes, then I've revved it up (in park, not neutral) to 5000+ RPMs. I can see the driver's side valve (the disconnected one) move just a hair, but it does not inflate. That tells me I must have a vacuum leak somewhere else that I haven't found yet. Please correct me if I'm wrong.

I seem to have several problems happening simultaneously. My plan of action (reasonable?):
1) Follow the guides to remove the manifold actuators so that I can clean/tune them. This apparently needs to be done regardless of any other problems as both arms are stuck and won't move by hand pressure.
2) While I'm taking care of (1), go ahead and replace the vac lines. I'm not sure about what else operates on the vac system, but I thought for some reason the intake manifold setup was segregated by check valves or something similar, so that if one system elsewhere in the vehicle failed not every vac-based system would fail as well. Shouldn't I see the vac chamber (I believe that's what that blue kong-dog-toy looking object is in the left front of the vehicle?) compress/decompress with engine activity?
3) Buy a new pair of linkage arms (from gruvenparts.com, I'm assuming).

I know I need those manifold arms freed. I also know that if my valves aren't inflating/deflating as they should, the link arms will do no good and I may even snap off the plastic manifold arms. Does this all sound reasonable?

 

I think the change over valve actuates at 4200 RPM. You should actuate them by connecting a vacuum pump to existing lines after the solenoid switch.

Changing all of the vac lines is cheap. Go to www.ecstuning.com and order the oem braided tube. Then you will need about 2' or so of slightly larger tube (I used washer line from Advance) for the secondary air valves on the back. ECS may have some larger tubing I would suggest that instead of washer line.

Keep in mind the vacuum system stems from 1 line so any leaks along the way will damper the performance. That's why it's good to check your parts with the Vac pump first. You should always try to prove the part is broken before you replace it.

 

OK so just so you guys can see from the inside. The actuators will only get stuck on the front of the engine and is relatively easy to correct the issue. I just happen to have a spare engine minus a few toasted valves.

 

I'm new to this site. I have an 04 A8 and there is a noise coming from the top rear of the engine. I was told it is a intake manifold actuator. The sound is similar to an electric motor turning a bad gear. Does any of this make sense? The car is still running fine. Also, about a week ago, I started smelling oil burning. There are no leaks on the ground, so I am assuming it is a valve cover gasket. Do you have any suggestions?

 

Fellas I just got my very first Aldi my boss actually let me get it until I can get it fixed and whatever and pay him off well the car was wrecked in the front end I saw it on the first it has a hundred thirty thousand miles on a 2000 Audi A6 2.7 L Quattro all right the car ran really good cuz my boss did try to put it back together when she was busted a little bit but it started running hot all right when it runs hot the oil pressure goes up to right at 2:50 right before it runs all the way over the middle is been running right before the middle but just ask my problem and I really need some help with it I've heard could be the auxiliary pump I've changed out the thermostat myself the thermostat in it was not bad I just need a little bit of advice if any could have anyone can help me thanks