I have a 72 gmc pickup with 350 small block the problem I am having is when I stop at a stop light the engines idle drops real low and almost cuts off so can anyone tell me what needs to be adjusted to bring the idle back up when stopped.also when stopped or slowing down my truck starts shaking real bad.

Have you checked the fuel line? My volvo used to do that when anything but premium gas was put in. It maybe be clogged but I don't know much about cars.

Check for a vacuum leak, also at a normal idle without giving it gas, do it have the same problem or it is at a normal idle. You can check for a vacuum leak with a spray bottle with water in it and spray around the area were they are vacuum lines. This is a carb fuel system?

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Originally Posted by 7up

i have a 72 gmc pickup with 350 small block the problem i am having is when i stop at a stop light the engines idle drops real low and almost cuts off so can anyone tell me what needs to be adjusted to bring the idle back up when stopped.also when stopped or slowing down my truck starts shaking real bad.

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Is this a new problem with your truck or did you just do a rebuild on the engine/carb?

First, the maintenance must be complete, you know what I mean?
Once the engine is at normal temperature and all loads are turned off, adjust the "Normal" idle screw and use small incremental adjustments to achieve the best results.

Attachment 16859


Secondly, more info about the "shaking real bad" issue: does it feel like the engine is causing the shake?