I dont know too much about this model... however, I'm in the market for one. So I'll try to help you out and give you some pointers until someone more knowledgeable than I comes.
When was the last time you changed the fuel filter? Think about getting that replaced.
As for the misfire... did you use an OBDII tool to scan and get the codes? Get the codes and post them here.
My guess: There was a small vacuum leak somewhere.