I think I'm doing something wrong. How on earth do you gain access to the air filter, on a 146ti? I've removed the four (visible) screws securing the lid, but the damn thing still won't lift-off. It feels as if it's still held down on the RHS, which just so happens to be inaccessable, what with the inner fron wing. What exactly do you have to do to remove the lid?
Have you tried sliding the top of the filter box towards the centre of the car before lifting it?. The picture in the workshop manual looks as though there are lugs along the side which would be under the edge of the wing- its not that clear though. I don't recall anything else from changing the filter on my Marea which is similar if not the same.
Johne is right! You have to slide the cover towards the centre of the bay. But first you have to let it free from the rubber pipe of the AFM before you slide it. I know it is a little hard but if you do it like this you won't ruin anything. Good luck and feel free to ask for more details as my English isn't my mother-tongue.