stephanie, the first thing you should consider , is to have any error the codes pulled of your computer. Places like Autozone can do it for free. See what you get. The other things that could cause this, including the power lossm could be carbon buildup in your throttle body, including the EGR valve as well as the MAF sensor. You did not tell us how handy you are, but a good cleaning of the air intake components may be a great start. Hope this helps, good luck.