having purchased a 2002 tt, have noticed something very odd. The car starts and runs fine, however I've noticed that on 2 occasions the tachometer bounces ,. While running at approx. 60 -65 mph and approx. 2500 - 3000 rpm ,the tach needle bounces as if on a spring, from say 3000 rpm to 1000 rpm. The engine never hesitates or coughs or anything of the sort , it runs fine. The bouncing tach is annoying and distracting though. One other thing , when it does this , I get to my destination and then have to let the car set for several hours before it will run again.The car will start with no hesitation, but as soon as i let go of the ignition key it dies..??? Can anyone advise???? Thanks.