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  1. #1

    Default Where's the o2 sensor

    1987 r-20 with 254ci

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

  2. #2
    TRPLXL2's Avatar
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    Norwalk, Ohio
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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??
    2004 Chevy Colorado
    LS1 5.7 swap/TBSS rear axle swap

  3. #3


    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

    - - - Updated - - -

    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.

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors,
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  4. #4


    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

  5. #5


    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.
    2004 Silverado 2500 Crew Cab 4x4, AMSOIL EA air filter, Granatelli MAF sensor, Throttle body spacer, Magnaflow exhaust (true dual to 2 in 1 out muffler), 6" ProComp lift (add a leaf and 5" superlift rear block), Bilstein shocks, 35's (Cooper Disoverer ST) and 4.10 gears, Rhino Liner, EGRUSA fender Flares and widow visors, extended stainless steel brake lines, firestone airbags w/onboard air compressor, Pioneer Avic X940BT navigation, Accel backup camera.
    1960 Land Rover Series II 88
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