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Re: O2 Sensor

On Fri, 26 Jul 1996, you wrote:

>Well with all the recent postings about O2 sensors, now I'm wondering if I
>should dig around and replace mine.  It's an ' 86 4KCSQ and has over 100,000
>miles I'm sure even though the odometer says 54,000 something.  I don't know
>if the previous owners replaced and sometimes the car idles rough.  Although
>now I'm wondering if I have a vacuum leak somewhere, and if I did where it
>would be.  Should I replace the sensor just to be safe?  It seems like the
>car should get better gas mileage than it does, but then that could be the
>way I drive! ;^)  TIA for the replies !
>' 86 4KCSQ
>' 71 AAR Cuda

The O2 sensor on these cars is primarily used for idle stabilization, so if
your idle changes rpm, "hunting", your sensor may be bad.  If not, I
wouldn't suspect a problem there.
Have you checked the injector seals?  On these engines, they bake, become
brittle, and leak air into the cylinders when running.  Typically, they are
good for 80k miles or so, so if you don't know, it might be a good thing to
check.  I replaced them on my 874kcsq (119k miles) a few weeks ago, and it
noticeably improved the quality of the idle.  

Let me know what you find out!  HTH!
QCUSA #1765
Founding Member NW Region AQC