LoSz

Regardless of how much boost i'm pushing (20 psi or 14.7 psi and anything in between), around 4.5k... i have a drop in boost pressure.

thing is... it boosts hard from 3k to 4.8k then drops like a waterfall then rises then drops again all the way to redline. its not a peak problem.

This is what I have done so far.

I originally thought it was my DV so i purchased at stratmosphere DV.

Installed it reverse. Same problem
Installed it regular. Same problem.

Purchased the adjustable cap.
Installed it regular. same problem.
Installed it reverse. same problem.

Then I made a diy pressure test kit ala Chris86 from Vortex <a href="http://68.101.149.4:8080/images/gti/pressure%20test.doc">(document)</a>

Really cool diy kit. Cost about $30 not including the air compressor.

Ran the pressure test.. no _apparent_ leaks.

MAF is strong. I have a spare maf at home and both have the same issue.

I clamped the map sensor. Unclamped it to test also. same problem.

So my remaining thoughts are:

a) coilpack problem? I don't see any misfire counts or problems in vag though. But then again coilpack problem happen so often on our cars...

b) Spark plugs? i have 10k on these plugs though. I have another set right next to me I can install.
No vag problems either.

c) I'm going to start pressure testing things piecemeal to see if I have any leaks (intake-&gt;throttle body, throttle body -&gt;remainder of the system). i did install my fmic and phenolic gasket so i might not have tighten everything down as much as i could have?

i'm pulling out my hair here! Any thoughts will be greatly appreciated.

Tee x2

it may be the ECU shutting your throttle plate (to save your engine..)
any lean codes??

carfanattic

Yes, check group 032. Maybe a leak in the hose to the fpr.

LoSz

I'm usually WOT when i'm testing this... so its open. I've logged it so i'll double check also. TY!

LoSz

32 read partial adaptation of 1.6 .. well within norms, right?

Kareem of Elise

I've been dealing with a boost loss issue over the last few weeks as well (mine would drop off to zero at 5k rpm in all gears)....

You said you cleaned and swapped your MAF. What about the coolant temp sensor? Those are notoriously bad and can cause boost issues. They are like $6 for the part and the O-ring. The part numbers are 059-919-501-A for the sensor and N-903-168-02 for the O-ring.

carfanattic

Yes, everything between +-5% is good.

RoberTT-WWCD

a frayed coilpack wire. Could be the problem.<ul><li><a href="https://forums.audiworld.com/tt/msgs/1260858.phtml">Thread here</a></li></ul>

LoSz

I have a spare one at home also. no difference. Thank you for your suggestion!

LoSz

I'm not really getting anything myself though. &gt;_&lt; I'll look into the prices for these also. Thanks!