Black Fuel Filter at Engine

[Coyote914]

I thought I kept getting Bad Fuel. I changed front and rear Fuel filters 3 different times over 4 or 5 tanks of Fuel. Each time the Truck would barely Run. When I pulled the Engine Fuel Filter it is Black kinda the color of used Engine oil.
Could this be a Oil Cooler going out or still got really bad Fuel?

Thanks in advance for any suggestions ....