I have a stock 2000 LS1 engine in an impala ss clone. Stock exhaust manifolds cats and dual 2.5” exhaust. I have tried auto ve and maf adjustment couple of time but I have had the feeling that I couldn’t trust the values of my lc1. It has always showed richer then Stoichiometric when in closed loop. (average 14.35 or so). First I used analog output and thought that there was a grounding issue. Then I used serial logging with the same result. When my sensor started to get code 8, I bought a complete new lc1. Now I have tested the new one, and I get the same readings with the new sensor and old controller, and the new sensor and the new controller. The sensor is located on top of the right exhaust tube right where it widens out for the cat, and there is no unusual back pressure. I have tested the exhaust at the tailpipe with a 4 gas analyzer and it shows exact 1.000 lambda.
How is it possible to get to rich readings from the wideband? What am I doing wrong?