98 gmc K1500 4x4 when it rains hard my truck won't start or it has a bad miss

Hello, To find this issue, the first thing I would do is take it to the car wash and isolate the area of water intrusion. My initial thought is the location of the computer. As you already know, it sits behind the glove compartment, and that is the same location where the air conditioning housing sucks in air. There may be rain water coming into the wiper cowl area or the air conditioning intake and running into electronics. Did the computer look water damaged when you removed it?