[William_Johannesson]

Hi!

This is my first post and I hope I'm posting in the right place

To start with:
I recently bought an E90 325I from a friend very cheap. I got it cheap because of all the problems the car has, most of them are mechanical, but some of the problems are "engine" related. I have no problem fixing the mechanical stuff, but I need some help with the magical components

The main problem I have is the code 2D0F. What I've found out is that it's MAF related, vacuum leak or bad MAF. I was very sure it was a vacuum leak, since the previous owner replaced the OEM air box with a shoddy aftermarket one with a big hole in it behind the MAF. Got an OEM box, and it didn't fix my problem. Googled the MAF sensor, and it didn't look like mine at all. Googled the number on my sensor, and it seems to be an IAT sensor.
When the car is cold, and I press the brake, the rpm bounces up to 1500 and goes up and down until i release the pedal.

So, heres my questions:
1. How do I know if my car is supposed to have an MAF sensor or an IAT sensor?

2. If I have the correct sensor installed, what could cause 2D0F?