Simple Question

[justin w ivan und stnt]

Was wondering if you guys could help out a newbie. What conditions would
occur if a 4-cyl efi motor (VW 1.8L supercharged from the factory) were to
not have the O2 sensor hooked up? Would the car run rich, lean just plain
crappy. Does a working O2 sensor vs. a non-working one really make that
much of a difference? My car is running like garbage right now and besides
the timing being off, the O2 sensor is also very suspect. 
   Please reply privately, I don't want to annoy any one wi/ my simple
question.

   Thanks,
Justin Ivan