Hello, just replaced my O2 sensor with digitool hooked up.....prior to replacent, it was reading all over the place -1.7v to +2. volts..........now with new one, it is reading around -.20 volts .............what the?  

I have an exhaust gas analyzer, and cannot get the mixture to change on the afm ( i am doing it per Bentley)  When I give it throttle i get a plume of black smoke............the idle stabilizer IS functioning, vacuum is 15in at idle, and the fuel pressure reg is within spec.  I did a test to see if the fuel system maintained its pressure after cut off, and yes, so no leaky injectors.

My afm is 3 months old.

Adam P

81 Vanagon Westy (The Brick)
70 Single Cab "Whitey" 
74 Beetle "Ol Yeller"
73 Transporter (STILL at paint shop)
1988 Vanagon Wolfsburg 
Used Vanagon Parts for sale (mostly aircooled)