I think my van is running rich. In the past few years I have replaced the AFM
and O2 Sensor, and for the most part my van is a reliable runner, but I have
noticed a general, declining power level, and longer "manditory" warm up
times. Can I check/verify this myself, or does the VW dealer have diagnostic
equipment that the typical shadetree mechanic doesn't have access to?  Can I damage
the engine by trial and error adjustments (of the CO screw)?

Thanks -
Brian Doss
'88 Weekendr Queequeg