86 Samurai cranks up fine and runs for about 5 minutes just great and then as you are going down the road at about 40 mph it acts as if it is either starving for gas or flooded I don't know which.  I can press the clutch in and hit the accelerator and it sound fine, let the clutch out and it runs good for a couple more minutes then acts up again.  I have changed the fuel filter and fuel pump and that hasn't helped. If you sit it in the driveway it will run just great.  Suggestions please....