Car: Stock 1990 Honda Crx Si

ok so heres what i think caused the problem.....somehow i got alot of water inside my motor, it has rained for the past 3-4 days non-stop and i seem to think alot of water has gottin into my motor because of a leak in my hood. I now have a check engine light and its showing code 15- ignition output signal, and code 16 - fuel injector.

The car runs...... it is misfiring and when i drive it, it also backfires.

What should i attack first? Can i test the fuel injectors without taking them out?? and do i have to relieve the fuel pressure before taking out the fuel injectors??