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  1. #1

    Default Sluggish at light throttle

    1990 Suburban 3/4 ton 350, th400

    So I have a problem with a stutter or a backfire (Cannot tell while driving).

    So far I have noticed,

    -Miss/backfire/stutter under load does this randomly.
    -TERRIBLE gas mileage
    -Rough idle sometimes?
    -Slight miss at idle
    -sorta hard starts, what I mean is it takes about 4 seconds of cranking to start...Goes away when warm.
    -revs increase when when pressing the brake pedal
    -Exhaust does not smell normal (I cant describe it, but its not right)
    -SES came on and off a couple times when raining, has not come on since.

    There is also more I have noticed and just can't remember off the top of my head.

    What I have done to test this,

    I have searched for loose connections, noticed at the CTS there is a torn wire right before the connector. The wires are still intact, break is so close to the connector I have to go to junkyard to grab a new one. Not sure if it is causing the problems.

    I have also tried searching for vaccum leaks with my propane torch and hose, did not work...Going to pick up some spray to look more in depth.

    I was curious is there a way to test the CTS lines after I get a junkyard connector to replace my bad one?

    Basically I think my problem is one of three things or all of them:

    -Vaccum leak
    -CTS Sensor
    -Fuel Pump

    Am I in the ballpark here? Open to any suggestions, I am waiting on my new parts for the brake lights and just kind off puttering around.

  2. #2


    My guess is fuel issue with your listed problems. They all can be traced to the fuel system.

    1996 Chevy Tahoe LT 5.7L V8 4X4 205,000+ miles. Built proudly at Janesville Assembly in Janesville, Wisconsin
    Basic mods: Lights all over, bunch of electrical work, and a couple cooling mods.

    Check out my other mods in My Garage:

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