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: Do you provide parts when repairing like o2,sensors

Yes, of course, any needed, or desired, repair parts can be made part of any repair order so that you do not have to go through the time and trouble of researching and procuring repair parts. I see you are...

Q: Mitsubishi Endeavor overheating. Got waterpump and belt replaced less than a year ago what could it be

This may very well be a bad thermostat as this is often a common culprit of many overheating issues on most cars. The thermostat regulates the coolant flow in and out of your car's engine. When this is stuck open...

Q: Suspect immobilizer is keeping car from starting.

I would ask for help from a mechanic to perform some diagnostics on your car to see what is causing your car not to start. They will be able to determine if there is an immobilizer that is causing your...

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...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.