Burning real rich after winter storage
If this is the same gas that was in the car when you parked it, the gasoline has lost it's punch.
Gasoline evaporates much faster today than it did 20 years ago. What evaporates first is the parts of the gas that give it octane. As gas evaporates, it gets thicker and darker in color. Gas here in CA will go from mostly clear to yellow, followed by orange. I've had this happen to a few of my junkers and the color of fuel seen though the clear filters has been this way many times.
I ran through the bad gas and poured in fresh Premium fuel and it ran right again.