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Is my "Throttle Positioning Sensor" bad?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by derek2002, Oct 25, 2000.

  1. derek2002

    derek2002 1/2 ton status

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    Is my \"Throttle Positioning Sensor\" bad?

    I have a 1987 K5 - TBI 350. When I first start it up, it takes longer to start than I think is normal. Then, it almost stalls, then over-corrects itself, almost stalls, overcorrects itself.... and so on. So, it revs way up, them almost stalls. It only does this for probably 1 minute at the very most and sometimes only for a few seconds. Is this a bad sensor? Maybe the "Throttle Positioning Sensor"? What do you guys think? Any help would be appreciated. Thanks in advance!

    Later,

    -Derek
    1977 3/4 Ton & Blazer Project (Body Needed)
    http://www.4chevy.com
     
  2. realsquash

    realsquash 1/2 ton status

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  3. derek2002

    derek2002 1/2 ton status

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    Re: Is my \"Throttle Positioning Sensor\" bad?

    Squash-
    No, I dont have a service manual, but I can get one from the local library. What are you thinking? Is there a way for the computer to check itself? Or do I need to get it "scanned" with a diagnosis computer? Thanks for the info..

    Later,

    -Derek
    1977 3/4 Ton & Blazer Project (Body Needed)
    http://www.4chevy.com
     
  4. 74K5Jay

    74K5Jay Registered Member

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    Re: Is my \"Throttle Positioning Sensor\" bad?

    I would replace the throttle position sensor. Thats what it sounds like and they usually aren't very expensive. There should be a way for your computer to check itself without taking it to a mechanic. If you have a chiltons or haynes repair manual it should tell you how.


    74K5Jay
     
  5. rich'90

    rich'90 1/2 ton status

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    Re: Is my \"Throttle Positioning Sensor\" bad?

    Something else you might look at is dirty injectors. Mine used to do that same thing. It takes a long time to start then all the sensor are telling it not enough fuel then to much fuel. The throttle position sensor really doesn't do much in idle. Also, change the fuel filter if you have them cleaned or clean them yourself. Another little thing is the idle air control valve. There are a bunch of things to look at. The computer should tell you if you have a bad TPS, if you are not getting a code then try the other things. Hope this helped, it confused me just writing it[​IMG]
    Good luck. Let us know what it was.

    Go heavy or Go home[​IMG]
     
  6. Captkaos

    Captkaos 1/2 ton status

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    Re: Is my \"Throttle Positioning Sensor\" bad?

    Derek,
    Sounds like an IAC valve, or you are producing a vacuum leak somewhere. I am just speculating though. Check the codes from the computer.

    Also, when you post a reply, if you select the reply button that is next to the person you want it directed at (assuming you are in flat mode showing all posts) they will usually get an email that you replied.

    Chris Lucas
    http://www.captkaoscustoms.com
     
  7. derek2002

    derek2002 1/2 ton status

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    Re: Is my \"Throttle Positioning Sensor\" bad?

    Captkoas-
    I usually click on the main post to reply, due to someone was bitching about not getting emails about posts. But, hell... if you have a post, its not that hard to keep track of it. Even if you have several. Anyway.. yeah, thanks for the tip.

    Later,

    -Derek
    1977 3/4 Ton & Blazer Project (Body Needed)
    http://www.4chevy.com
     

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