My 1997 jetta almost drove my crazy and killed me several times...So please help me to find out what is wrong with the damned car.(I checked with mechanics but they told me nothing was wrong.

It started around 1 year ago. When it was raining, I can not start my car. I can hear the sound "tu tu tu tu..." which mean the engine was trying to start. After 3-4 times try, the car can be started. But if I stepped the brake, the car automatically shut down and I need to restart again. I took my car to the garage, they can not find anything wrong. The same story happened several times. So I consulted my friend who suggested me to change to coil and spark plug and I did it. And I never got the problem for 4 months even when it was heavily snowing. These days, it is raining a lot in my town and the horrible experience come again! The difference is that there is no problem for me to start my in the raining days. But once I started and drove for 2 minutes, the car automatically shut off and can never re-start again. One time I was under the traffic light!! The worst thing is the car can be restarted by jump start and run well when the rain stop, and the mechanics can never dig out what the ****ing problem is! Everything is fine, they told me. But I will die in my car.

Please give some advice and save my life.