I'm asking this for my friend, he opened up his AEM box and found that the intake pipe has a little hold near the end that attaches to the throttle body, what is that hole for?

 

we need some more info please, but it is probably for the o2 sensor

 

It's a hole for the sensor that goes into the stock airbox. I think it measures airflow, or temperature, or somehting.

 

it has nothing to do with the o2 sensor
it connects the valve cover to the intake

 

Actually no, I'm not talking about that hole. I know about the o2 sensor one, but there is this littel hole, by the looks of it, it kinda looks like a hole for a nitrous nozzle or something, does this make sense to anyone? It like right near the sleeve where you connect to the throttle body

 

you probably bought a used AEM. Somebody made a hole for nitrous.
peace

 

Either for the IAT sensor or pcv. No 02 sensors in the intake.