1993 Honda Accord Engine cuts out after driving for 10 minu

The car does'nt stop running, it starts fine and runs good most of the time. There is two times that I notice it cut out and lose power or feel really sluggish and that is 10 min into my drive in morning or sometimes throughout day while I'm driving around 55-60 mph. It will ussually act sluggish and cut out for a minute or two and then it starts running fine. But it stays running and does'nt stall out. Would a catalytic converter show these signs? Another thing the car used to do but seems to have stopped now, is when you put it in park the idle would rev up and down, but I was told this could be an ildle air control valve? I put new plugs, wires, cap/rotor, pcv valve, water pump/timing belt kit, and it was smog and came out good all in the last year.