Air box lines?

There are 2 lines that come out of the airbox. What are they for? I have some problems with my 95 jetta just up and dying. They replaced a temp. prop. but the top line of these 2 keeps coming off. I wonder if this is causing the car to stop?

Thanks.

Those are for your evaporative emissions system

would those cause the car to stop if they came off durring driving?

no but you would notice it. there will be a diffrence in the car. just pop it back in they almost never come out though there in there pretty tight, if changing your filter, don;t disconect them from the air box, disconnect them from where it seems the two wires are connecting