I can't figure this out. I'll be driving along then the turbo just starts making that high pitched whistle of the recirc when you're on the gas and no boost builds. Then randomly it will stop and I'll boost normally again. Noticed it does it more after building around 12-15 psi and shifting, then it leaks in the next gear for a bit then stops. 2009 LNF 2.0 Stock K04 with Aftermarket K&N Typhoon. Rest of the car is stock. 116k miles.

 

I had something similar happen when my bypass valve ( on the intake manifold ) started going bad

 

Okay I'll take a look into that, thank you.

 

Also test your boost bypass selenoid, your BPV for leaks, purge selenoid for failure, make sure your intake is tight

Can you log the car at all?

 

I could take it to a local tuning shop and have them do it probably. I don't have a tune or an OBDII reader or anything. It might be the Bypass Valve failing, I did vacuum hose reroute that's posted on the forums where you take the vacuum hose closest to the dipstick and pull it out then pull out the one that goes into the Manifold and take 5" of hose and connect it directly from the port into the intake manifold and the valve closest to the dipstick and that seems to have worked for now

 

I'm not sure if you are talking about bypassing the boost selenoid, bypassing the vacuum tank or something else.

 

I bypassed the Vacuum Tank. Sorry I should have elaborated.

 

The vacuum tank is a common boost leak location as the car ages. If you car is fine now and your fuel trims are good, then I wouldn't worry about taking it to a shop.

I have ran with it bypassed for 125k miles. Not problems that I can tell. The vacuum tank was not used on several other LNF cars so it's for sure not needed.