2002 Suburban 2wd MPG has dropped off suddenly!

subburbanitesubburbanite Member Posts: 2
edited July 2015 in Chevrolet
175000 on the odometer, engine running smooth, no warning lights etc.
Any ideas on what the problem might be and how to troubleshoot it?
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Answers

  • eliaselias Member Posts: 2,209
    Most likely/inexpensively, the O2 sensor(s) failed and need replacement, and the computer will throw an OBD code soon, maybe already has silent/no-warning-light codes. (Scan it with a 20 dollar scan tool, and check for codes.)

    Possibly transmission is not shifting into highest gear and/or with its lockup-torque-converter-clutch.
    (Watch RPM, and compare with specified RPM engine should be turning at 60 mph on highway - if it's more RPM than manufacturer spec, then you have a transmission problem.)

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