Just baught a 98 Jetta GL 2.0 used from a private party. 230xxx miles on it. The oil had been changed before the guy put it up for sale. I drive 80 miles a day for work. The car ran great for about two weeks. Slowly it began to shake in the front end while going up hill and losing power a bit. The shaking has been getting worse and increases when gas is pressed 3/4 of the way down. I looked at the tires and there is a weight on the front driver side tire. So, they apear to have been balanced. I've only used 91 octane. The engine is clean with no leakes. There is a slight noise from underneath when starting from a stop. It sounds like a door stop that has been pulled back and released. Any ideas?