While driving my villager this afternoon it suddenly started chugging, rpms fell and would not respond to the gas being pressed. I had to pull off the road. Pressing the gas made it die. We changed the fuel filter, the roter, the distributor cap and air filter and also added a fuel treatment. We started it cold and it idled fine. Once warm(5min), it chugged and died. We think it seems like it's starving for gas or air. Any advice? We have not changed the plugs or wires yet. Wondered about mass air sensor?