[fatddrfreak]

Ok, so this is my first post, but I've lurked around for a while. I have an automatic 04 g35 coupe. The Service engine soon light came on for the first time yesterday. I had just put about $40 worth of gas in the car and it was almost full. I started driving and then I noticed the ses light. I babied the car home and went online to check it out.
I read so many things about the gas cap so I checked it. It seemed tight, but I gave it a couple of clicks to see if it would tighten up. I manually cleared the light with the gas pedal. I drove the car 3 times since then, but not very far. The 3rd time I drove it, I drove to zaxby's, which is about 5 miles from my house. I waited in the drive through for about 10 minutes. I shut the car off and restarted it. About 1/2 mile from my house, and upon returning home, the service engine soon light came back on. I cleared the code again and put the gas cap back on. I havent driven it again yet.

I dont know if it just happened to do this when I got gas, and something else is wrong with the car. I see how to clear codes, but not how to read them or what not. Is there a tech article or anything that could shed some light on locating the ecu, putting it into diagnostic mode, and then going from there.
I just bought the car less than 2000 miles ago, had it service and looked at. It was a lease vehicle before I bought it. It has about 72,200 miles on it.

Any thoughts, tricks, or ideas I should know about?

Any help would be greatly appreciated.
Thanks