I read that replacing a faulty oxygen sensor can improve your gas mileage by up to 40%. true or false? ?

in your opinion..and why/how?I read that replacing a faulty oxygen sensor can improve your gas mileage by up to 40%. true or false? ?
true - a faulty O2 sensor will put the computer into ';limp home'; mode, which is only concerned with not leaving you stranded. Some vehicles will only stay in limp home mode for a limited number of starts, due to EPA demands.





without the O2 sensor signal, the computer is just guessing at the correct air/fuel ratio based on other parameters.I read that replacing a faulty oxygen sensor can improve your gas mileage by up to 40%. true or false? ?
False.


It will surly improve your gas mileage if you replace a defective O2 sensor - but not at the overly optimistic figure of 40%.


The O2 sensor ';trims'; the air fuel ratio determined by a look up table in the computer based on numerous vehicle sensor inputs - the key word here is ';trims'; - it does not determine initial or fixed pulse width of the injector - that's determined by the strategy in the computer program.


The computer does not guess at the air/fuel ratio - it is directed to a specific value by several different inputs - the O2 sensor is only one of these criteria - others include the throttle position, coolant and ambient air temperature, engine load and so forth. That's why each PCM is calibrated for a specific vehicle to take into account the many variables such as gear ratios, transmissions, vehicle types, etc.....