Itermittent turbo loss

[carl p]

Hi folks,
Im new to this forum and this is my first post hope you can help me.

Ive had my Passat 1.9TDI 1999 for 6 months now and everything is fine apart from a intermittent power loss with the turbo.When driving sometimes when i put my foot down hard say in 2nd gear the turbo seems flat then pulls hard then drops off, then when tried again pulls hard with no problem.It seems like something only works when it wants to.Car has a regular a service, this problem brings no black smoke or worrying noises and everything else runs great.Could anyone give any advice on this or had this problem.
Thanks.

[boschmann]

There is a valve that controls the wastegate that commonly fails, it's commonly called the N75 valve. It is under the hood on the inner fender by the air filter and has three vacuum hoses & an electrical connector. There are specific proccedures to testing it that require a VW scanner or equivalent. It will often set an engine trouble code when it goes bad. Is your check engine light on?

[carl p]

Cheers for your help Boschman,
Over here in the United Kingdom we have had flash floods and very heavey rain for 3 days when the problem occured, but today its been sunny and warm (typical UK weather) and its seems to have gone away,and all power is now back.Could this have been the problem or is it likely to come back?No lights are on or other indications of fault.
Cheers
Carl.

[boschmann]

TDI's also have problems with the Mass Air Fow (MAF) sensor. Usually the problem isn't intermittent though and it has a loss of power all the time, particularly noticeable that it can't get up to highway speed easily.