Yesterday on my drive home there were various hills that were not very steep but they were long hills. Going 65mph it would drop down to about 50 mph. It gave a sluggish sound like it was fighting to keep a constant speed. But heres the thing if i used my cruise control it was fine, once my mph started to drop it would drop a gear and stay at a constant 65. When i wasn't using my cruise control i tried giving it more gas, slowly pushing the gas pedal all the way and still no change. 50pmh was the constant speed. No check engine, plugs have almost 70,000 on them, new fuel pump, and cold are intake. not sure if the wires and coil packs were down. Going to find out tonight.