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Old 01-24-2009, 02:44 PM   #1
1984Silverado4x4
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Engine RPM's

My truck has a 305 with the stock Quadrajet on it and a 4spd transmission.
When I drive a vehicle with manual transmission I sort of expect the RPM to drop back to idle speed as soon as the clutch is disengaged. On my truck however when I disengage the clutch (depending on how fast im going, what gear im in, and engine temp) the engine will rev way up for a few seconds then settle down to idle. Couldnt tell you what it revs to as it dosent have a tach but I imagine 2500RPM or so.

It happens the worst when the engine is cold and im only doing 25mph in 2nd gear and come to a stop sign or something.

Anyone have ideas on why it would do this?
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Old 01-24-2009, 07:42 PM   #2
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Re: Engine RPM's

It sounds to me that you could have a vacuum leak somewhere, Maybe a loose/cracked vac. hose or possibly intake ?
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Last edited by Restrorob; 01-24-2009 at 07:43 PM.
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Old 01-24-2009, 09:12 PM   #3
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Re: Engine RPM's

It sounds like your carb throttle shaft is hanging up and not returning to idle position, when you relieve the load on the engine. Take a look at your throttle return spring and see if it is not too weak, or maybe the carb has worn bushings in it and the shft is hanging up there.
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Old 01-25-2009, 09:50 AM   #4
1984Silverado4x4
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Re: Engine RPM's

Ill take a look and see about both of those

Thanks guys
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