1985 Ranger 2.3L 4speed automatic
I just purchased my first Ranger at a local non profit auto auction. It has 46k miles on it and seems to have had a good life. I drove it home and checked it over. Someone had just installed a new battery, plugs, air filter, fuel pump, and changed all the fluids. I checked out the brakes, and drivetrain and everything seems in good shape.
Old Blue, as I have named it, has some hesitation and sputtering on start up but generally has decent power. I took it out for a test drive on the highway this morning to clear some cobwebs. It would accelerate to 65 mph but then when I tried to hold it there and just cruise awhile after a couple of minutes it seemed to start bogging down and losing power. If I hit the accelerator it would down shift and come back up to speed. I gave it bout 50 miles of highway time just to see how it handled and this behavior did not change.
So I am looking for ideas on where to start troubleshooting this old Ranger.