'91 PASSAT starting problems

I have a 91 Passat that I am having problems with, all started when it was raining and I was driving with no problems, I arrived home and when I tried to drive again, I did not start. I thought that something was wet and I decided to sta at home and wait until it get dry. The next day I tried and everything was fine.

The next week it happen the same thing, one friend come and he told me that he had the same problem with a '92 jetta and told me that the sparks were swimming in oil.

I took the car yo the mechanic and he changed everything, it costed me some money, but when we tried to started it remains the same problem.

I need your help to find out if this is a sensor problem or something else.

Thanks in advance

My 92 passat had this problem. The first time I experienced it was when I degreased the engine and trans. It has also happened after I just drove through a puddle with the car. What I have found with is that the Coolant temperature sensor on the back of the block above the transmission had water inside the pin connector shorting it out and causing the cooling fans to run all the time until I dried the connector out. Also, the three pin connector at my distributor was soaked with water and oil, once again shorting the circuit and stalling my car out. Watch your tachometer next time it acts up, if the needle starts jumping all over the gauge face check out the three pin connector at your distributor and see if there is any water or oil sitting across the terminals.