Hi

I've had my Evo IX MR for about 6 months now. Just recently (about a few weeks ago) I noticed the engine was idling pretty high, about 1500 - 2000 RPM's. However, it doesn't do it ALL the time. Some days its normal, and others...not so much. Haha. And even more recently (about a week ago) the Service Engine Soon light came on. I haven't really noticed anything different about the car (aside from the high idle) and it also doesn't stay on consistently. It'll be on for a few days. Then off for a few days. I've been ruining my eyes for a few hours scrolling through thread after thread to find out what I can do. (It's not the gas cap! >_<) Please keep in mind, I'm definitely NOT car savvy. Haha. Please explain/help me in a simple way? My questions are:

1. Can anyone shed some light on the high idle? And what might be causing it/what I can do to fix it?

2. Anyone have any ideas on why my SES light is on?

Help would be GREATLY appreciated! =]