Ok so i was on my way home from work in my 240Z and it was running fine but for no apparent reason it started to sputter and run crappy.  I limped it for a few miles while it was running really crappy but then it started backfiring when i shifted and losing power and wouldn't gain any power no matter how much throttle i gave it.  After a while I pulled over and I couldn't get it fired back up.  Its the stock 2.4, I was thinking maybe I got some bad gas? I filled her up yesterday at shell with 93.  What do you guys think?  Any input would be greatly appreciated.