general problems of the 2000 Chevrolet C1500

2000 chevy silverado1500 v6 stalls when driving. No check engine light to indicate any issues with engine. Dealer replaced catalytic converter but cannot offer any reason as to why this occurs. I have replaced the spark plugs, distributor and rotor button. This happens sporadically and can not be traced to any one source by me. I have noticed that the last couple of times it was raining. This has been on going for about 4 months. When this happens I lose the ability to use the brakes and is very hard to control.