Mass Air Flow Problems

[stangman]

I hope someone can help. My wife was driving our 03 pathfinder the other day and it started loosing power dramaticly then died and would not restart. She waited a while and it restarted but would die upon putting it in gear. After towing it home we used the code reader on it and it shot a code saying the IAT sensor was bad. After a trip to the parts store I returned with a part that our model year does not have since it is combined with the MAF. My question is I have been told by NISSAN that 2003 pathfinders had two different MAF and it depends on the production date which one is needed. Ours was manufactured in 2/2003 and is a five pin connection. What is the difference and will a failed MAF cause the vehicle not to run at all. I hate to replace it only to find that it is not the problem. Someone else has to have had this issue. Please help!