1998 Mitsubishi Legnum Car wont start after raining

Hi there have just replaced fuel, pump and filter, and crank angle sensor, was running perfectly fine until it rained the other night went out to try and start the car it wont go it is trying to start and when it does it kinda coughs and splutters then stalls on me, we have assumed that there is water getting in somewhere but not sure where, it is a ST GDI and we just dont know what else to try we have just recently yesterday sprayed whole engine with WD-40 to try and drive any moisture out to see if that is the problem, any suggestions as to why my car would be doing this would be awesome dont want to keep throwing money into the car parts that dont need to be replaced if they dont need to be