Having some small issues with my brakes on my 2000 audi a4 1.8t. Usually they work great, nice grab and seems to be a good amount of pressure in the brake lines. But for some reason randomly when I first start the car, or if I'm on a hill *front end up* then the brakes seem to have no pressure in the lines and I have to fully press the pedal to get the brakes to engage. Any ideas?

 

The audi also has a weird problem when backing up. Seems like the transmission slips and then catches and jerks. Any ideas?