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Idle surging

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 89K5guy, Jan 24, 2006.

  1. 89K5guy

    89K5guy 1/2 ton status

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    When I am at idle especially in drive, the idle surges up and down.Any ideas on what to look for?:confused:
     
  2. mouse

    mouse 1/2 ton status

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    Start by looking for vacuum leaks. Replace any lines that look questionable, then use a small propane bottle to search for leaks. Do not light the propane, just turn it on and point it towards various items on/around the intake. If the idle increases/smoothes out, then you've found the leak. The propane will be drawn in at the leak and stop the leak from making the fuel/air ratio too lean.
     
  3. K5Greek

    K5Greek 1/2 ton status

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    Im having the same trouble with mine. Ive replaced the 02 sensor, wires, plugs, egr, new thermostat(put new rad. in) and Ive checked for leaks with no success. Not sure what to do here either
     
  4. MuddQueenK5

    MuddQueenK5 Registered Member

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    Another method you can spray carb/TB cleaner in "trouble areas" and it's the same principle, if the RPM's go up then you have a leak.
     
  5. NEK5

    NEK5 3/4 ton status Premium Member

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    how can you check for vaccum leaks????
     
  6. MuddQueenK5

    MuddQueenK5 Registered Member

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    I think he is saying to take propane (don't light it obviously) and just run it over the vac lines. If the idle goes normal then that area is the cause?

    You may also be able to use soapy water. Just spray problem areas (where the vac lines connect or possible kinks) if you see bubbles, then you know where the leak is.
     
  7. NEK5

    NEK5 3/4 ton status Premium Member

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    thanks
     
  8. chevyk2500hd

    chevyk2500hd 1/2 ton status

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    You can't use soapy water. It is called a vacuum leak for a reason. It will suck the water into the engine not blow bubbles. I don't recommend doing this. Carb cleaner or starting fluid are good choices.
     

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