Installing air/fuel meter, anyone know where to tap in on ECU or where to find an ECU Diagram?

You don't tap into the ECU, You...
 

Tap into the O2 sensor. The color should be a brown wire (at least I think it's that color. I installed one in my old B5 passat 1.8t awhile back). Where do you plan on putting the guage?

Darin

WRONG! - O2 sensors in the 02 and 03's work on a 3-8 volt system... won't work with current meters