Some signs a oxygen sensor is failing are rough idle when the vehicle is warm ( at operating temp ), loss of power or "stumbling" when the vehicle is warm, poor fuel mileage, and improper fuel mixture ( car running too rich ). Testing of a oxygen sensor is done with a digital volt meter and back probes. Different oxygen sensors have different numbers of wires to them depending on the vehicle. Use your repair manual and/or wiring diagram to determine wich wire is the signal wire. With the car warmed up and running put the positive lead with a back probe to the signal wire and the negative lead to ground. The voltage should vary up and down between .2 and .9 volts. If the voltage stays consistently above or below .45 volts the sensor is faulty or the engine hasn't reached operating temperature yet. Let it idle longer and retest to be sure you don't have a false reading.
bad oxygen sensor bad map sensor
Check engine light would appear.
The check engine light will illuminate with a code(s) directing which O2 sensor is bad.
Low gas milege is an indication of a bad oxygen sensor and/or it's wiring. A lack of power, increasing vibration in car's floor and cabin area(s), high RPM's at highway speeds.
Being pulled over a lot for speeding
banging into gear
When the oxygen sensor goes bad, the check engine light goes on.
When an oxygen sensor goes bad a car will burn gas at a higher than normal rate because it will not be producing as much power as before. The oxygen sensor checks the amount of exhaust.
It's simple. The engine will work on a much higher RPM or it will shut down itself without giving you any other signs.
An auto xray scanner can determine if a O2 sensor is bad.
It sure can.
When you have a bad oxygen sensor your car may consume a lot of gas. Your car may also drive slower.