a MAF. (mass air flow) sensor. Just had one go in my 2002 Buick Regal and it NEVER threw a code until the very end. By the time it did, it was stalling and acting up horribly. MAF'* are relatively inepensive and extremely easy to install. Yours is only 6 years old roughly: I seriously doubt it'* an ignition coil. Try removing and cleaning the MAF (see instructions in this forum: just do a search under 'mass air flow' sensor) If that doesn't work you can replace it, or just wait for the code to go off, because it will eventually.