Here's what I have:

1998 Civic EX with intake, header, exhaust.

On my way home tonight my check engine light came on, the car started running like poop, and the speedometer started dancing all over the place. It rained pretty hard today so I'm not sure if something could have gotten wet. I popped the hood and everything looked dry, my air filter was dry, distributer cap was dry, all the plug wires were tight, nothing seemed out of the ordinary. I disconnected the battery for a good half hour and then started it back up again. At first it ran like normal, but then the check engine light popped back on and back to running like poop. Any guesses on what I could check next?