1990 Mazda RX-7. Been trying to find out why I%26#039;m getting such bad mpg... Unplugged the oxygen sensor but it didnt even give me a %26quot;check engine%26quot; light unplugged (works with the key on, drove around with it unplugged... still no %26quot;check engine%26quot; light)... If I change my oxygen sensor, will the car recognize and use the new readings from the oxygen sensor?|||the o2 sensor tells the computer to regulate the amout of fuel the cyl gets by reading if its running rich or lean, this is the reason that ur mileage is so poor, because the injoctors are probably just putting out alot of gas since they dont know what to do|||Back then. the O2 sensor indicator was usually mileage triggered. You should not necessarily get a light in your car.
I know my 1993 Isuzu truck was set to trip that light every 90K miles and I had to swap a screw int eh gauge cluster to turn it off.
Also, ALDL and OBD1 are much more tolerant/lazy when it comes to emissions issues.
