Engine fluctuations

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Sep 7, 2006 | 11:33 PM

blackknightjoe

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8th Gear

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From: Lindenhurst IL

Engine fluctuations

Can anyone tell me what would cause engine rpm to cycle between 10K and 5K in park (auto trans). I have a 79 vette, 350 with a Holly four.On the way home today I had to keep it in neutral to keep the engine from stalling. I thought at first...idle adjustment. But now, even in park, it won't idle.

Sep 8, 2006 | 12:22 AM

...Roger...

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From: Dayton, Ohio

Do you still have an EGR valve?

Sep 8, 2006 | 12:32 AM

BigBlockk

Drifting

Joined: Sep 2004

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From: North Bend Ohio

What is the initial advance set at?

BigBlockk

Later.....

Sep 8, 2006 | 07:09 AM

blackknightjoe

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8th Gear

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From: Lindenhurst IL

Yes I do. I visually looked for anything obvious and couldn't find any. Thanks for any advice you may give.

Sep 8, 2006 | 07:10 AM

blackknightjoe

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8th Gear

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From: Lindenhurst IL

I have no idea at the time, since I just picked up the vette after being the shop. It was recently tuned ( so I was told ).

Sep 8, 2006 | 07:40 AM

...Roger...

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From: Dayton, Ohio

Quote:

Originally Posted by blackknightjoe

Yes I do. I visually looked for anything obvious and couldn't find any. Thanks for any advice you may give.

Most EGR valves you can put your fingers up inside and feel the diaphram move-make sure it moves freely----If you have a vacumn gun pull a vacumn and see if diaphram moves-----tap around lightly with small hammer and see if it seats itself----At idle you should notice a big differance if it is open or closed-----Or take it off and clean and check it and make sure it holds vacumn and fully closes-its easy to remove.