check your map sensor? intake filter clean? osnap was having a similiar problem and it turned out his timing was slightly off. There was something else wrong, too, but to this day we don't know what. Something involving the intake, because he brought his car to our shop for bodywork and it sat for a while. Being nice, I gave him a new intake and filter since I had the stuff laying around. Problem had fixed itself by the time he came to pick it up.

So... I would say..

1. Check MAP sensor.
2. Check air intake for leaks/replace or clean filter
3. reset ECU
4. Check timing

That's the only stuff I can think of, because like I said osnap's b16 was actinging similiarly, and once those 4 things happened, it was golden.