I have heard that you should not use 02 feedback control without an airpump. Why not? It seems to me that the 02 sensor is way upstream of the cat which is where the airpump injected air for emissions, right? I want to run 02 feedback not only for the mileage, but also to cut down on the choking exhaust fumes at light cruise and idle. My WB02 only functions at >13 volts, not always an option with my underdrive pulleys, especially at idle.

 

works fine with me, but then again i have a cutout. with it closed, it still works allright.

 

if it works then use it

my car will try to go into cosed loop at idle and light throttle conditions ... pain in the ***, ymmv