I see. I know that my carb has the check needle under the acc pump squirter. I was thinking that it may not be sealing properly causing the fuel to bleed back down like sqzbox and cobalt are talking about. I have a punch that will work. I might give this a try first before pulling the metering block.
So the purpose of this needle is to prevent fuel from seeping back down into the pump diaphram? Since this only happens after the car has been sitting for a little bit or been crusing for a while, this sounds like a very likely cause. Thanks!