Whenever I use my vents, heat, AC or defog, it blows exhaust ridden air at me...

How can I fix this?

It was really horrible in the winter when I had a friend in the car and we were trying to stay warm, and I just couldn't stand sitting in one place with the vents blowing at me, it smelled so horribly, I experimented and it does it in all the conrtol positions, this needs to be fixed...

 

You've got an exhaust leak under the hood somewhere.

 

And if you do have an exhaust leak under the hood, you probably also have a leak at the cowl seal at the rear edge of the hood. That should prevent any underhood air from entering the HVAC intake:

 

You could also have an exhaust leak and a broken heater box.

 

Wonderful, I know I had an exhaust leak under there, still, I guess I'll have that taken care of...