all of a sudden power loss

I just got this car and it was performing well when rpms 3000 and over....at lower rpms it was cutting out and only if I was on the gas to shift down or manually shift the transmission or overdrive off switch would it not cut and hesitate.so i was looking at the plug wires and noticed they had never been changed. so I got new spark plugs and wires. as I changed the plugs one was very different than the other 5. it smelled of fuel and was wet.next was test drive and no more low rpm cutting out....so that was a victory for me....until I was on the freeway and got on the gas and no power at all.as long as I stay light on the peddle it will operate normal but 2800-rpm and up it performs terrible as I'm on the gas and I'm looking at my tach. 3000 rps is when it starts to sound like its got a k&n air filter or no air filter. lots of sound but being made. but power is lost....what did I do? I would rather have it cutting out like b4 I made my repairs.it was better than now....at least if i kept the rpms up it would haul and was fun to drive...now I dont even want to pass slower cars in front of me please help.