2002 silverado 5.3
 

i have a 2002 chevy siverado ..every time it rains i lose engine power and the check engine light flashes .if i turn the truck off then started again the problem goes away?????? i changed plugs and wires one wire was rubbing on the steering shaft and i thought i found the problem but now it still continues...any help would be great .cheers 334000kms

My old Dodge 1500 with the 5.2 did that. It was getting water into the air intake because the splash guard in the wheel well was missing.