Check engine light came on yesterday and the only think that may have caused it was cleaning the engine the other day. I used a very light amount of water. Could that have caused this? We never felt a misfire or any running issues related to this code.

I got the code read at Autozone and picked up new plugs and a coil for $100. I'm planning to replace the coil first and see if it works, then the plugs. I'd love some input here as I am new to these cars. I ordered the repair manual but it hasn't arrived yet; can anyone share how to do the coil?

Thanks!