Well, I've been out of state for over a week and this has been bugging the crap out of me not being able to troubleshoot it. My coworker has a 4.3 Mercruiser, same Chevy 4.3 that displayed the same symptoms and it was the coil. My coil was a ball of rust so it was replaced. So, plugs, wires, cap, rotor, and coil are new. Nothing changed performance wise. Fabbed up a couple of test hoses to use with gauge. Between the tank and the fuel pump/filter assembly, I am getting around 1 Hg at idle. Fuel line pinched off, around 3 Hg. Maybe pickup obstruction or bad pump? Didn't get a chance to test between fuel pump and carb as I ran out of daylight. Trying to figure out how to get the pickup tube out of the tank which is a Moeller plastic tank and the tank flexes bad with torque applied to the fitting. If it ends up being the pump, is there any tips to clean it out? Seems like minimal hours on an electric fuel pump. BTW, the ASV appeared to be good, no corrosion internally and the ball and spring move freely.