Nissan Repair: Sensors...Where do I Start?, intake air temperature, flash floods

Question
My engine check light came on like 2-3 weeks ago and my car was driving fine so i ignored it. Then yesterday when i was driving my car it just turned off while i was driving...I couldnt turn it on for a bit but eventually i got it to run enough to get home. Then the next day when i went to work it drove fine no problems..So i took it to Autozone to get my engine light read..I got back three problems,
1) PO130 - Oxygen sensor 1  
2) PO110 - Intake Air Temperature Signal
3) PO325 - Knock Sensor 1

I have a feeling the flash floods here in Arizona screwed up my sensors but thats besides the point...I dont which one to start with, which one is the most important to fix and where i can take it besides a dealership.

Answer
Nick,

Depending on your model the sensors are as follows.  If you have a V6 the front oxygen sensor is located on the front exhaust pipe close to the engine.  If it is a 4 it is in the same place on the exhaust pipe close to the engine.  Looks kind of like a spark plug with wires coming out of it.  The second is the air intake sensor and it is located close to the air filter where the air enters the air filter box.  It is a small sensor that plugs in.  It could be that yours is disconencted as this is the most common problem.  If not then replace it.  The knock sensor is under the intake on the V6 model and that means that you have to remove the upper intake to replace it.  On the 4 it is under the intake but you can snake a tool in to get to it.  Purchase a new one and you will see what it looks like.  In all cases disconnect the battery first and once you are done reconnect it and the codes will be cleared.