One day I was driving in heavy rain and while I was idling, I noticed the engine having trouble...rpm needle was moving, and battery voltage was lower than normal, and i could definite tell something was up. Even when i was driving around the engine was having trouble responding.

i went home and I got a code for my 1997 Z28 and it says "random multiple cylinder misfire"

I have noticed that my car acts this way usually only happens when it is raining out. I had driven it for a solid week in dry weather and it ran fine...then it rained again heavily today and i had the same problem.

Have any ideas what it could be? I honestly have no idea were to start looking for the problem, i know a little about the LT1, but not too much.

 

sounds like moisture in the opti aka distributer . A common problem. You have a 97 so you have the vented opti make sure the vaccume hoses are on the opti good and snug and you may want to consider pulling the opti and sealing it better.