Skip the auto shop - Our mechanics make house calls

Q: Failed the emission test. I'm suspecting a bad oxygen sensor.

asked by on

Took truck through emissions failed by 800 points on both Idol and and rolling dynoRPM test truck seems to run ok has lots of mileage on 02 sensor engine doesn't have any misses has high mileage but seems to run OK doesn't burn any oil I'm thinking that it 02 sensor might be bad it only has one in front of the cat cat is new OBD2 . , has throttle body fuel injection which seems to be working fine we just replace the air filter and I'm waiting on the oxygen sensor to run it through again. Plugs are new I'm going to change the plug wires and the rotor and cap also before I run it through If it fails again I guess I'll go for the waiver because in Arizona after you spend $300 on a vehicle from 88 to 95 you can get a waiver only good for one year. Sucks because I like the truck but yet I might have to dump it for nothing if I can't get it through emissions and I don't want to do that I'm not a rich man thanks for your help any help is appreciated even if you can't thanks mike

My car has 210000 miles.
My car has an automatic transmission.

A: Hi there. Change out the spark plug wires, ...

Hi there. Change out the spark plug wires, put sea foam in the vacuum system to clean the internals of the engine and change the oil and filter. Then drive the vehicle around and fuel up with Techron fuel.

When you go to the emissions station, run the engine hard, but not enough to damage it. This gets the catalytic converter hot and makes it work real good. When in line, do not shut off the engine and keep it running. Try to be the first in line if possible or early in the morning when the line is short. This will help with after driving around hard. Your truck should pass emissions with a good outcome.

If you need further assistance diagnosing your engine, then seek out a professional, such as one from YourMechanic, to inspect your exhaust system and help you with preparing for the emissions test.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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: Emissions test

According to the Arizona DMV website, the emissions test will perform the following during an inspection: On-Board Diagnostic (OBD) Test: OBD tests monitor vehicle components and evaluate any system problems. Gas cap test: Makes sure the gas cap can...

Q: Failing to maintain proper voltage after replacing the starter the alternator and the battery

It sounds like you may still be having problems with the voltage regulator maintaining the proper voltage. When the voltage regulator is not working properly, this may result in the alternator not supplying enough power to the battery, resulting in...

Q: How do I time my 1997 Chevrolet K1500

Hello. There is a specific procedure that must be followed in order to ensure that the ignition timing is correct. The distributor can only go in a few ways so the engine needs to be set at top dead center...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
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.