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TBI Idle Adjustment

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Rocky91, Sep 25, 2002.

  1. Rocky91

    Rocky91 Registered Member

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    Does adjusting the idle screw effect rpm's while driving or just while at an idle? I increased the idle on my truck so it would idle better, but it seems to rev higher while driving. I was just wondering if it is related?
     
  2. bckinblk

    bckinblk 1/2 ton status

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    What idle screw are you talking about?? In the front of the linkage on the drivers side there is a metal cap that if you remove it you can turn the adjustment screw with a tourqe bit .Is this the screw you turned???
     
  3. Rocky91

    Rocky91 Registered Member

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    Yes, that is the screw I adjusted.
     
  4. bckinblk

    bckinblk 1/2 ton status

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    I also did this to my rig a while back .The idle is computer controlled and nomatter what I did my truck still ran funny it would surge and sputter it just did,nt run right I messed with the timing and changed plugs etc and still no luck.So I changed my o2 sensor and it fixed it right up the only problem was the idle screw was set to high for the new sensor so I had to bring it back to its original position and its been running great since ..Good luck hope this helps................
     
  5. 90K5

    90K5 1/2 ton status

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    If your have a rought idle try replacing the IAC sensor
     
  6. Rocky91

    Rocky91 Registered Member

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    I going to replace the IAC tomorrow, if that don't do it I'm going to take it to a mechanic. It has another problem too, it stalls out while driving. Not sure if they are related.
     
  7. TopOff

    TopOff 1/2 ton status

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    Sounds like a VACUUM LEAK!

    Good luck.
     
  8. Rocky91

    Rocky91 Registered Member

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    I'm not sure if it is vacuum related or not. It idles bad in park and under load, but it is more noticable under load. I've checked the vacuum lines over and can't find any that look bad, I've also checked the TBI-to-manifold area for a leak.
     
  9. TopOff

    TopOff 1/2 ton status

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    I had the brake booster off (leak) and it acted the same way. The ISV compensated for my leak. Then again, I have an aftermarket TBI with a GM computer.

    Good luck.
     

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