I have seen where it is TIME that will cause this. That is it takes time to get the engine warm, so here is the fix...
Replace both fuel filters, when doing so, leave the pre filter disconnected from the car, not the engine. Then take off the fuel cap. Next use shop air to blow into the line that goes to the car not the engine. This will clean any debris from the strainer. Prime and start. Hope this helps.
1981 280GE SWB
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