Well I changed out the plugs with new motorcrafts, and the engine shake went away. Or parts guy doesn't carry Bosch Copper core. I'll have to order some. The Bosch P4's lasted 45 minutes until they almost shook the engine apart. Advanced Auto took them back. I drove all day and can't get it to shake anymore.
As for the coolant overflow. I couldn't find a block tester today, my all wise NAPA store guy said, "We ain't got no fancy smanchy tester like that for that Mersadieys Ben$$$$." This guy wasn't firing on all six either. I did notice on the inside of the radiator cap that the inner rubber pressure valve was not seated correctly. It was sort of angled in the hole.
I still smell antifreeze inside the car. Maybe the heater coil has a small leak in it. The smell is intermittent.
Is bubbling in the tank normal when the temp rises? Should the radiator hoses to the water pump be tight with pressure when hot and running. My other cars fill tight with pressure.
The compression today on the cylinders was 170 to 175 on all 6.