Problems accelerating in 2002 ford taurus?

I have a 2002 ford taurus w/ roughly 87,000 miles on it. Recently it has been losing power (mainly if i'm on the interstate!) when I reach a certain speed (around 65-70mph) although it has done it at lower speeds also. It feels almost like i am running out of gas, but I am not. The check engine light came on for a few days and now is off but i still have this problem occasionally. I have used a couple of fuel additives to increase the quality of the gas, and I have used a fuel injector cleaner. I have been told that it could be anything from the fuel filter to the transmission (hope not). I am trying to drive back home this weekend and don't want to be stranded on the interstate. Any help?