Improve Mileage with new O2 Sensor?

[doylna]

I just had a major tuneup - new wires, plugs, cap and rotor, oil change, valve cover gasket, distributor shaft seal and a couple of other things. My tires are properly inflated. The car idles at 850rpms, but, there after highway driving (like at a tollbooth), the idle doesn't drop immediately, it takes about 5-7 seconds to get down to 850rpm. I haven't cleaned the IACV in about 4 years (30K miles).

My mileage is still middling at best with an average of about 24-25mpg (average over several months) on the highway with speeds of 70-75 mph. I've read that many are getting better mpg than me.

Would replacing the 02 sensor (which has never been replaced) in 196K miles improve fuel economy?

[NorcoAccord]

it couldn't hurt, but are you 5 speed or automatic. Either way changing the tranny fluid couldn't hurt.

[doylna]

5-speed, tranny fluid is new within 20k miles.

[NorcoAccord]

I have been thinking about trying this , I am not 100 percent sure it will work but it may be worth a shot.

[Old School]

Only if it is bad. The OS can be tested to see if it is in spec. Do some trouble shooting before you throw money at your car.

[doylna]

Only if it is bad. The OS can be tested to see if it is in spec. Do some trouble shooting before you throw money at your car.

That's why I'm asking, rather than just replacing. How do you test the 02 sensor - it's not listed in the Haynes.

[ExplodingCake]

That's why I'm asking, rather than just replacing. How do you test the 02 sensor - it's not listed in the Haynes.

To determine if the oxygen sensor really failed , turn on the car and let it idle & acquire a voltmeter. Disconnect the oxygen sensor connector and do this exercise. Increase the idle speed of the vehicle and check the voltage reading. The reading should be in between 0.5 volts to 1.0 volts. When you decrease the idle the voltage reading should be in between 0.0 to 0.4 volts. If the oxygen sensor fails within these exercise , replace it with and OEM replacement.

[Old School]

If you want to know more about o2 sensors this is a pretty good link.....




o2 LINK

[doylna]

Awesome. Thanks very much!

[doylna]

If you want to know more about o2 sensors this is a pretty good link.....




o2 LINK

That is a great link - thanks very the find.

[F20A CB7]

Good info here guys, great job.

[Losiracer2]

but if you own an EX CB7, where the O2 is in the downpipe, how would you check the voltage and rev the engine at the same time?

[Bcozzi71]

i have a ex and the o2 is under the car not in the downpipe??

[mtnbikaah]

but if you own an EX CB7, where the O2 is in the downpipe, how would you check the voltage and rev the engine at the same time?

get a friend to help?

[5spd'r]

I have been thinking about trying this , I am not 100 percent sure it will work but it may be worth a shot.

Thanks for the link, too bad they want so much for that, sounds similar to adding acetone to the gas though...smoother idle, lower emissons, and about 3-4 mpg gain.