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2000 GMC Jimmy Question: What should the RPM's be when my 4.3 liter engine is at idle?

 

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, Muskogee, OK, June 23, 2012, 07:59
 Rookie

Tune-up idle speed

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    June 23, 2012, 09:20
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     Master

    Idle speed is controlled by PCM. What problem are you having?

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    , June 23, 2012, 09:25
     Rookie

    Knocking at 600 rpm

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    , June 23, 2012, 12:26
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     Master

    When you say knocking, do you mean an actual bootom end knock. If so that has nothing to do with idle speed.

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    , June 25, 2012, 01:59
     Rookie

    My 2000 GMC Jimmy makes a knocking noise after it warms up. There doesn't seem to be anything else wrong with it, it runs fine otherwise. I have asked several mechanics and they are stumped. I was told it could be a wrist pin? It idles at 700 rpm, is that too low? What else could cause a bottom knock?

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    , June 25, 2012, 12:50
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     Master

    It is 12 years old. Not knowing how many miles are on the engine it could be an oiling problem.

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    , August 01, 2012, 01:21
     Master

    The idle speed is usually onthe underhood sticker with the engine/emissions info.Most are between 650-750 at idle in drive.If it's just one or two wrist pins as suggested while it's running kill one cyl at a time and see which cyl. the noise goes away at.

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