1986 Toyota Pickup Enigine runs rough then stalls intermitt

Engine Performance problem
1986 Toyota Pickup 4 cyl Four Wheel Drive Manual

Hi!
We're having a problem with our Toyota running rough at times and then stalling out. It doesn't happen all the time, and there doesn't seem to be any pattern. This last time, it drove perfect for 2 weeks and then started acting up. It will become hard to start, run rough, strong gas smell and then will stall out. We have replaced the fuel pump, fuel filter, spark plugs and wires, cap and rotor and the air filter is fine. Also checked wires, connections at battery and vacuum hoses. We checked the coil for spark and that looks fine, too. Any help would be greatly appreciated. Thanks!