Chevrolet Repair: 99 chev venture, rough start, barking up the wrong tree, control modules

Question
This vehicle is driving me nuts.  Each and evry time it rains the car will loose a couple cyls on start up. it will sit there and blurp along for about 10 min, then run fine. Will continue to run OK all day with several starts. Have had new coils, wires and plugs put in. Same exact thing. We have placed colored paper over the engine and sprayed water over the car. Cannot find any trace of water on ignition, just down the edge of both fenders. I must be barking up the wrong tree.

Your thoughts please

Answer
HI LARRY, WELL I THINK YOU ARE ON THE RIGHT TRACK,BUT I THINK YOU JUST DID NOT REPLACE THE PART THAT IS CAUSING THIS...I WOULD OF THOUGHT WHAT YOU REPLACED WOULD OF TAKING CARE OF YOUR PROBLEM..WHAT I WOULD LIKE YOU TO DO IS, WET THE ENG DOWN LET IS SOAK FOR 5 MINUTES AFTER WETTING IT DOWN, NOW IF YOU CAN GET THIS CAR IN A GARAGE WHERE THERE IS NO LIGHT AND START IT UP SEE IF YOU SEE ANY IGNITION SPARK LEAKING AROUND THE COILS OR WIRES OR WHAT EVER.IF YOU DO FIX THIS OF COURSE,BUT I SUSPECT YOU WILL NOT SEE A LEAK.[YOU COULD ALSO DO THIS AT NIGHT FALL AS WELL]. IF YOU DO NOT SEE ANY SPARK LEAK,I HAVE SEEN CONTROL MODULES DO THIS,THIS IS WHAT THE COILS ARE MOUNTED ON TOP OF..LET ME KNOW HOW THIS GOES FOR YOU AND GOOD LUCK,,,,TOM...