I have never seen a D valve fail. I would go over the BSH hardware and pull it off and reinstall to make sure it's seated. You could have a shop pressure test the system. Look for unhooked hoses around the PCV or boost tap if you have a boost gauge.

 

im doing the pressure test tomorrow let hope its a simple fix. by the way i heard cruise control is controlled by the vacuum... so if its a leak then its should work right? but my cruise control does work..... heading toward fuel injectors now......

 

lol youre right 2wdBlazer!!! i did a boost leak test using the the tennis ball trick and i found it. Turn out my PCV breather hose is leaking. now the real problem is removing the hose and replacing it with a new one. any suggestion on removing this.....http://www.ecstuning.com/Audi-B7_A4-...alve/ES281099/

 

Any chance your car is still under warranty? If so, your problem is as good as fixed (for a small $85 fee to you). That should include the new part as well.

It's worth looking in to.

 

I told you! Not sure on what the problem is? It should be simple to replace.

 

no its not the lower pcv valve hose cost me about 50 bucks. my main concern is how can i get the the other end under the intake manifold ... might have to remove the throttle body....any suggestion?

 

If you are tight on space snap it off with a scredriver or cut it off. The new one should just pop on or clip on. Does it look like a self clicking connector? You should not have to pull the TB or anything major.

 

I have replaced the hose. I test drove the A4 and saw it boosting at 19psi (torque apps for android) ten minute later....hesitation occur then MIL came up.
so since that same day I received my vegcom. i plugged it up and found this=
2 Faults Found

000768 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - Upper Limit Exceeded - Intermittent - MIL ON
Freeze Frame
Fault Status: 10100001
Fault Priority: 0
Fault Frequency: 3
Mileage: 118753 km
Time Indication: 0

Freeze Frame
RPM: 2837 /min
Load: 66.2 %
Speed: 60.0 km/h
Temperature: 93.0∞C
Temperature: 43.0∞C
Absolute Pres.: 1010.0 mbar
Voltage: 13.589 V

000769 - Cylinder 1: Misfire Detected
P0301 - 001 - Upper Limit Exceeded - Intermittent - MIL ON
Freeze Frame
Fault Status: 10100001
Fault Priority: 0
Fault Frequency: 3
Mileage: 118753 km
Time Indication: 0

Freeze Frame
RPM: 2837 /min
Load: 66.2 %
Speed: 60.0 km/h
Temperature: 93.0∞C
Temperature: 43.0∞C
Absolute Pres.: 1010.0 mbar
Voltage: 13.589 V

and also this

1 Fault Found
01826 - Sensor for Steering Angle (G85); Supply Voltage Terminal 30
000 - - - Intermittent
Freeze Frame:
Fault Status: 00100000
Fault Priority: 3
Fault Frequency: 3
Reset counter: 31
Time Indication: 0

Freeze Frame:
Hex Value: 0x0000
Hex Value: 0x4222
Hex Value: 0x0024
Hex Value: 0x0194
Hex Value: 0x0001

any idea?

 

I am having the exact same issue...did you ever figure out what it was??

 

I had my car in to the dealer the other day for a scheduled oil change. While there, they also did some recall work (changing a valve flap). Apparently it's not a publicized recall. They're only doing the update if you already have your vehicle in for something else.

May be worth calling them to ask about it.