I would definitely check the fuel pressure. Mine did much as you describe when I had inadequate pressure.
I “borrowed” a fuel pressure gauge from autozone or oriellys and installed it in line in the line from the tank. I was only getting around 30-35 psi. You should have 50ish to run right. There’s a sock filter at the intake of the pump assembly in the tank and the pump itself that can be replaced.
Also, check your exhaust screen as they can clog. I take mine out occasionally and clean with a brass brush.