If the car runs all day at 80 MPH, there is nothing wrong with the fuel filters and replacing them would be a waste of money and time. Filters do not clog proportional to time but to the contaminates in the fuel. If there were no contaminates in the fuel, the filters would last forever.

The theory that filters have to be clean to work is a lot of bunk. They work perfectly up to the time they will not pass enough fuel for full power operation of the engine.

P E H