First: stop putting hi-octane gas in it. It's not good for it, and is a BIG waste of $$$. Did you fill it in a different region from where you live? Did you fill it very close to the change of seasons? Either could result in you burning the wrong formula of gas. Read this caption:
Second: misfires & bucking in that car aren't necessarily related to fuel. It's often coils burning out, intake leaks, or even the residue of a repaired intake leak. Be careful with the spark plugs because they're also known to eject.
Third: I wouldn't clean the MAF, but if you feel you have to, use CRC brand MAF cleaner - nothing else. And follow the instructions on the can.