1994 Pontiac Grand Am Chugs!?

have a 94 grand am coupe. I just recently had the fuel pump and filter replaced. Now when I drive it at 45 mph it starts to chug and then it gets a little better as I accelerate and then at 65 mph it really starts chugging. Tonite when I was driving I lost power in my car for a moment. I have had the alternator replaced not too long ago as well. All fluids are fine and I noticed a air hose was lose and plugged it back in hoping that was the culprit but still having the same problems. Any help would be greatly appreciated.