pp performance
#26
it will affect fuel economy by preventing your ecu from going into closed loop function... When no signal is received from the O2 sensor your car will stay in open loop and run off programmed maps (it already does this during start up when car is cold and WOT).... these maps are static so they are not adjusting like your car would be in closed loop function using o2 info, thus less fuel efficient (running rich)
I have down pipes non cattes