i need help i am a marine in japan and my wife has the car. he is having mad backfire it sounds like a cannon and it stalls when it does that please help

Could be o2 sensors, plugs, dead cat converter...quite a few other possibilities as well. If she isn't mechanically inclined, I suggest she go to a local mechanic and have him diagnose the problem...then post his diagnosis back here...and perhaps we can help you from there.