vw&audi

I have a 1.8T NB '01 and is almost 19,000 miles now, but is not the same anymore.
They (VW) replaced the knock sensors and is a bit better now but not enough. I think its a pressure lost somewhere but they can't find it (or don't want). So I've heard that some valves are the problem most of times, like the divertment valve or bypass, wastegate, hose system, you name it.
Please giveme your advise, where should I look first? What parts can be responsible for turbo lag? How can I test it (also without VAG tools)?
Please help!
I've tryed NB forums but I think there is more knowledge here, and the engine is almost the same.
Greetings from Mty., Mexico

WYSIWYG

is good enough

xr4tic

to make sure they are not loose or broken. The stock diverter valves are known to go bad (more so when chipped)
You can check the vacuum lines and hoses by spraying starting fluid (ether) around them when the car is idling. If the idle goes up, then you have a leak. Try not to spray ether on the turbo or exhaust.
VWs are known to have faulty MAF sensors, maybe this is a warning of a potential MAF failure.

A VAG-COM would be really helpful.

vw&audi

Thanks fellows, and the boost gauge is almost done, but what is an AF gauge? Air-fuel ratio? Is it possible that boost reach its peak even with a leak?
And I don't have any check engine light now regarding the MAF sensor, Do you think could be faulty anyway?
If I can get a VAG-COM, What section is the right one? What should I look for?
Thanks again.

WYSIWYG

lean mixtures may dictate you have a pressure leak between MAF and turbo. rich mixtures between turbo and manifold.
if theres a leak the turbo will work harder to reach it wastegate actuator settings.
if you dont have idling problems, better check your BPV, reset your ECU, clean your MAF (dont touch! even with qtip, just spray with denatured alcohol)