1999 Firebird PLEASE HELP

I recently bought a 1999 fire bird with only 19000 miles on it. Yes only nineteen thousand. I've been driving it for about a week and all the sudden the car started to sputter along. It felt like it lost a lot of power. Like it was running on only 4 cylinders. It's not spitting smoke, the engine isn't knocking I think it could just be the coil packs. I've been looking around on the internet and it seems like this is a common problem? What do you guys think I should do?????!?! I need help!