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Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by walt88, Nov 4, 2001.

  1. walt88

    walt88 1/2 ton status

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    This is annoying. My truck runs fine until i get to a light. I dont have a tach but you feel the the RPMs drop every few seconds. I tried better gas and some Drygas and still no good. I havehad a tune up about a year ago and an injector service. Its a 350 TBI. Any comments would be great.

    350FI/700r4/NP208c/10b's ORD 4" Shackle Flip/ORD Disconnects
     
  2. chevyracing

    chevyracing 1/2 ton status

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    could be a vacuume leak or the weights in the distibutor are worn at the pivot if applicable.

    Like to go sloppin' 'round in da mud in a rapid fashion....=) [​IMG]

    <a target="_blank" href=http://community.webshots.com/user/chevyracing>http://community.webshots.com/user/chevyracing</a>
     
  3. 90BlazerK5

    90BlazerK5 Registered Member

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    Mine does the same thing... my tach says it holds at a high of about 800 rpm, then drops to as low as 400 for brief times. I'm going to check for a vacuum leak..

    Where did all these damned dirty apes come from!?!
     
  4. fr8train

    fr8train 1/2 ton status

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    Could be the throttle postion sensor. I had the problem but when I was in 2nd or 3d gear at 1/4-1/2 throttle. Thought my trans. was going out. Turned out to be the sensor.....I replaced the TPS and map sensors togther and had no problems, knock on wood, to this date.

    <a target="_blank" href=http://community.webshots.com/user/thatguydrew23>http://community.webshots.com/user/thatguydrew23</a>
    "JEEP....SO GIRLY, BARBIE HAD TO HAVE IT"
     
  5. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    It could be also be an 02 sensor. My brother in law's truck did the same thing and it ended up being a combination of bad 02 sensor and dirty injectors.....



    <font color=blue> NEVER FORGET, NEVER FORGIVE, NEVER SURRENDER<font color=blue>
     
  6. Burbinator

    Burbinator 1/2 ton status

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    A bad O2 sensor would more than likely trip the check engine light.

    As mentioned earlier, it's probably a bad TPS or MAP sensor, possibly even that "black box" on the passenger side of the intake that controls the EGR vacuum.

    The learning curve is a toll road...ride with someone who has already paid!
    <a target="_blank" href=http://photos.yahoo.com/abshort1>U.S.S. Nimitz II</a>
     
  7. walt88

    walt88 1/2 ton status

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    Definatley is not an O2 sensor, I just replaced it. I am going with 3 different things. TPS, MAP, or vacuum leak. Going to check for vacuum leak. Probably that. Also i thought TPS was only on a TPI. I guess not.

    350FI/700r4/NP208c/10b's ORD 4" Shackle Flip/ORD Disconnects
     
  8. Burbinator

    Burbinator 1/2 ton status

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    The TPS is on the passenger side of the throttle body.

    Good luck and keep us posted!

    The learning curve is a toll road...ride with someone who has already paid!
    <a target="_blank" href=http://photos.yahoo.com/abshort1>U.S.S. Nimitz II</a>
     
  9. walt88

    walt88 1/2 ton status

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    Thankyou, I will update this post tomorrow. Hopefully will find the problem.

    -Walt

    350FI/700r4/NP208c/10b's ORD 4" Shackle Flip/ORD Disconnects
     
  10. 90BlazerK5

    90BlazerK5 Registered Member

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    Finally got a chance to get under the hood this evening, and found something, but I'm not sure what it is. Coming off the drivers side of hte TBI unti is hte throttle assymbly. Well, one of hte links coming off the throttle assymbly is a short arm that goes back to a rubber diaphram located near the firewall. The rod was broken off. Could the broken rod possibly be causing the rough idle, and what does this assymbly do? Sorry for being ignorant on this, but all I have is this Haynes manual right now, and its not very helpful! [​IMG]

    Where did all these damned dirty apes come from!?!
     
  11. 90K5

    90K5 1/2 ton status

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    I dont know if your on here anymore...but was doing a search and found this...your cruise doesnt work does it? thats the rod thats broke.
     

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