I know many people are hesitant about making mods to their vehicles, but I say have fun with it.

I would try doing an open air cone air filter, rip the stock one out, and replace it. The nice thing is they are inexpensive (you could pay 200 bucks for K&N but why?) and they don't EVER need replacement, just cleaning every 50,000 miles.

I bought mine from Ebay, for 7 dollars. Its about 15 minutes of your time, and that could be the reason you are having trouble also.. Air is restricted, because of that paper filter (stock air filter).

Just FYI. You will get a little boost in power.. not much, and better throttle response in the process, and it most likely will fix the problem.