is this possible?

 

I think it is possible, but I could be wrong.

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1989 IROC-Z 5.7L
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how often are u recomended to change it any ways?

 

Entirely possible... our computers are mostly stupid unfortunately.

 

i know youre supposed to change it every 30000 miles, and i had the cat replaced a little over a year ago, and shortly thereafter, it slowly began to run like crap and run crappier as time wore on, and i know they didnt change the sensor but im thinking they mightve screwed it up taking it out or putting it back in...hmmmm....the car runs real lean too...

 

YES, change that thing. A lean condition is a good indicator of an O2 on its way out. I had a CTS problem for a LONG time and the computer didn't show a code fr a few months. It was driving me insane.
bsa

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"If they do not run, Then they will die." - Stonewall Jackson
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The O2 sensor is probably dirty. It can't "see" any oxygen in the exhaust, so the computer interprets this as a rich condition, and tries to compensate by making the car run lean.

 

Often, sensors become "weak" rather than flat-out fail. When they become weak, they will not trigger a code, but they give weird results. This is where a scan tool becomes useful. After you have done enough scans of the motor, you begin to recognize normal operation. When you notice the results seem to get out of the norm, you know that you have to start looking at something.

But remember, just because one sensor is giving you unusual numbers, does not mean the sensor itself is at fault. Often, another part that is "going out of spec" may cause another sensor to give unusual numbers as the "system" is attempting to compensate. It is a "system", which means "all parts working in unison".

 

I don't think my O2 sensor has ever been changed. And it has 155,000 miles. Guess I better change it huh?

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Never mind





[This message has been edited by 8Mike9 (edited June 29, 2001).]

 

got under the car and looked at it today-man that thing is crusty

 

Glenn has the right idea, but I refer to them as "lazy". They don't switch as often or as fast as they should, and therefore the engine cannot repond to changes like it should. Also over time, they become degraded and loose effectiveness. Unfortunatly, like mentioned before, our computers are not setup to be able to detect this, and therefore it is recomended to change it every 15-30K

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If a dirty O2 senser causes a lean condition then what will cause a rich condition? At about 70,000 miles my gas mileage went from 20 MPG to about 15 MPG and I had black smoke coming from the exhaust, I changed the O2 senser and that fixed it.

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