Couple of things possible.
Someone installed new intake gaskets and blocked off the passage under the intake or the passage is plugged with carbon. I had one that was plugged off.
Your symptoms are typical cold intake problem.
THe fuel vapour reverts back to a liquid when unheated. No fuel vapour to the pistons. Lean bog.
Do you have the stock heated air cleaner that has a heat tube running to the exhaust manifold?
I see your other post. The cold intake will answer your question over there.