For now, I think the best thing you could do is find a way to clean the system up a bit. Seafoam through the throttle body is an easy way to clean it up a bit. Also, clean up your MAF sensor with CRC MAF cleaning spray. Combined they should run you about 16 bucks and will take about an hour of your time max. Be sure to have a person handy for the Seafoam since you need to keep it from turning off when you put it in.
If this doesn't help then it's probably something like a timing chain tensioner or cam position sensor. I've been hearing a lot about those two lately. I'll probably look into replacing mine in the near future and a preventive measure.