My 1998 f150 runs strong at first a minute later runs rough ):Most tell me a coil pack

You should get a check engine light and see what code it throws u but if not, sounds more like the egr valve is dirty, check and clean and see if it helps, coil packs can get expensive unless u really need to replace them

Also you can unplug coils one at a time, any change in engine roughness means the coil is good. If no change, its a bad coil. Sometimes you wont get a CEL. Mine didn't

I got he same problem no check engine light, I don’t know what’s happening, did you figure it up?

its the blinker fluid or the muffler fluid. love me