2002 Jeep Wrangler Cylinder Misfire

I live in south Florida, and recently we have gotten a lot of rain. I have driven through some pretty big puddles, and since then my engine has been shaking quite a bit. It also doesn't have the power it used to. The check engine light blinks when this occurs. I used a OBD-II reader and the code that it gave me was P0300 - Multiple cylinder misfire. It also said that there is an emissions leak. My guess is that moisture may have gotten in the distributor cap, the distributor cap is cracked, or moisture got in the spark plug wires. I don't have a lot of experience working on engines, and want to check the distributor cap, but can't seem to locate it. I think it is hidden between the firewall and engine. I just can't see it. Any suggestions? I am considering replacing the spark plugs to see if this helps too. Any advice would be appreciated. Thanks!