2001 Volkswagen Jetta Loss of power

Hello I have a question and in need of you expertise very bad. I feel the car is unsafe so help would be grateful. My Girl friend has a 2001 Volkswagen Jetta. It has pretty close to 150000 miles on it. She will be driving down the street and it will lose power. Almost stall on her. You have to take you foot off the gas pedal and let it sit for a second then press it again and its fine. But when it looses power it like you stepped on the brake. So would like to see if you knew what it might be. I have a couple of ideas what it might be but don't want to start spending money on random ideas.