Fuel/Power problem

I have a 1991 Acclaim and it has some problems.

It acts like it pulling a trailer and really bad gas mileage.

Now let me tell what all I've done.

new Tran
new crank postion sensor
new TPS sensor
new altenator
new distributor and bug
new fuel pump (twice)
new fuel filter
rebuilt throtal body (kit with plate under it)
new vaccum hoses (almost all if not all)
new plugs and wire
new air filter
oil changed with new filter
fule tank cleaned out

for the most part thats it other than tires and break system.

I can't find out why thers no power and why its bogged down even with the AC off. When the AC is on it feels like i'm towing a trail and boat.

Please help