We did a car at work which had O2 sensor. It resulted in more power
but did not save gasoline. Observationally (looking at the exhaust ) it
had richened it up because was much blacker.
We have almost finished building the Very simple EFI O2 sensor
offsetting device....Bob Boyce found it.
http://better-mileage.com/memberadx.html
It isnt that hard to build - I am only slightly able to do electronic work,
but had never built on Vero board before. Found it fun, confusing at first
but once you get going , no problems.
I tried hard to keep it neat, but being first timer , it tended to get all bunched
up in certain areas. Would you like pic & send to your email.?
Glenn , See Ya.