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Where's the o2 sensor

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by Davidh, Mar 20, 2013.

  1. Davidh

    Davidh New Member

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    1987 r-20 with 254ci

    i can't seem to find the O2 sensor. Any help?
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  2. TRPLXL2

    TRPLXL2 New Member

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    Did they even use 02 sensors back then?? I don't think they did, but besides the point what is an r-20??
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  3. Pikey

    Pikey Moderator

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    I am pretty sure that R-20 refers to the model of the suburban. The original poster would be better off just calling it a 1987 3/4" ton Suburban as no one knows what the heck an R-20 is. I think that he meant 454 not 254. I did not think that O2 sensors were used back then. But, looking at the autozone website they say that they sell them for that truck and motor

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    To find your O2 sensors follow the exhaust. If they are there they will be in the exhaust pipe somewhere. That is is the owner before you did not remove it.
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  4. Davidh

    Davidh New Member

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    Sorry was in a hurry. Did not edit the post. It is a 454. R-20 is 3/4 ton rear wheel drive. When I got it smogged here in California the mechanic told me that it had a bad O2 sensor because it surges a little and gets poor gas mileage. I will look closer but so far have not found it.
    it is getting about 8 miles per gallon on the hiway and I think it should be a little better on the hiway. this is a new truck to me that I bought just to tow a camper. Thanks for the responses
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  5. dsfloyd

    dsfloyd New Member

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    a 454 3/4 ton getting 8 mpg highway is a little low (closer to city mpg). if there are 02 sensors there would be one before and after each catalytic converter (once again if it has either of those in that year). Basically will look like a spark plug sticking out of the exhaust with a couple wires out of the top.
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