Q: Hi Patrick, I was told by my machanic when my engine light sparked in that I need a oxegen sensor, and said that it has to be fixe

asked by on

My 2003 Mazda needs a oxygen sensor,, but when I took it in to fix it my engine light wasn't on anymore and my mechanic did an inspection pass it saying it was a perfect inspection.. One of the best!!! He says, but now my car kinda skips at times and my gage at times goes up and down but it dosent get hot or anything... WhAt does this sounds like??

Oxygen sensors are tested using an automotive scope or oscilloscope. In your circumstance, if there are more than 100,000 miles on the sensor, the sensor output should be verified on a scope. The mechanic should show you the output waveform on the scope and explain its meaning. You will see a varying amplitude signal (like a sine wave, although rough) running between about .2 and .8 volts with a transition rate (from high to low voltage) of 5 to 7 times per second. If you desire testing of the oxygen sensors, and an evaluation of the hesitation issue (which could be due to failing oxygen sensors; they do not last forever and they will often NOT set the check engine light if they are merely "failing" versus completely "failed"), please request an engine diagnostic - oxygen sensor scope testing. If you request that service, the responding certified mechanic will get this taken care of for you.

If you have noticed that the engine operating temperature is in a different range than what you have previously observed, there is probably an incipient problem with the cooling system. That problem could be as simple as a sticking thermostat, faulty radiator cap or malfunctioning radiator cooling fans. This can be checked out if you request an engine cooling system diagnostic. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Hi Patrick, I was told by my machanic when my engine light sparked in that I need a oxegen sensor, and said that it has to be fixe

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Will the intake runner solenoid give a P0171 or and a P0174 trouble code? 2005 Ford F150

Hello - the short answer is "No". The P0171 and P0174 codes you mention are "lean condition" Bank 1 & 2 respectively. Intake runner solenoid issues are P200x codes. Your loss of power may be a result of a fuel...

Q: Why is my 2009 Ford Taurus still running hot after I put new water pump, new thermostat on and flush radiator twice but it still runs hot.

You may still have air pockets in the cooling system. If you do not bleed out the air it will still overheat. After bleeding all the air out of the engine and heater core then see if it still overheats....

Q: Engine turns off when the first gear is shifted

Hello. The most common cause of the car dying once it is put into gear is the transmission torque converter or the fluid level of the transmission. If there are leaks present from the transmission, I would suspect the fluid...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.