Audi A4 1.8T looses power when accelerating
 

Hi,

When opening the throttle to accelerate I my Audi A4 1.8T 2001 looses power and regains it only after I lift my foot off the gas. Acceleration is only possible at low revs. I got the following error codes:

first:
17563 Long-term fuel-trim-system too lean (bank-1)
17545 Fuel trim: Bank 1 (Add): System too rich
18010 Power supply (B+)- terminal 30 - low voltage

after clearing the codes and after approximately 10km drive the following codes came back:

16684 Random misfire detected - any cylinder
16685 Cylinder #1 - misfire detected
16686 Cylinder #2 - misfire detected
16688 Cylinder #4 - misfire detected
17584 Bank 1: O2 (lambda) correction behind catalyst control limit reached

Please help me: where to start the repair?

Many thanks in advance.

Seems like air leak in the intake path or bad MAF ?