Bad Gas (I think)

I put gas in my truck the other day and the check engine light came on . It's an R/T and I used 93 octane. Everytime I hit the gas and the RPM's get around 1500, she starts shaking. She stops when I take my foot off the gas. Anybody know how I can check codes for the Check Engine Light..or if the bad gas is my problem?

Any suggestions would be helpful. Thanks

I am having the same problem. Have had in the dealership twice...they replaced the O2 Sensor twice (charged me once), but say they can't reproduce the problem. It happened again. At around 1500 RPM, the engine shakes bad. I just want to get the thing fixed so I can get rid of it!