2002 Chevy Blazer, no power

This has  been going on forever! First symptoms
were that the cat suddenly lost power while
attempting to go onto the freeway and refused to
go more then 30 mph. Drove the car about 20 miles
to get it back home in this condition. Codes run
called for cam sensor, and distributor. After
replacing the sensor, it was  thought the spider fuel
injector was faulty so it was replaced. Meanwhile
the car sat with half a tank of bad gas for several
months. After the fuel injector was replaced, then
the fuel filter replaced. Seemed to be much better
at first then suddenly worse on idling. Pulled the
gas tank, cleaned it and found the fuel pump in bad
shape, replaced it, replaced the fuel filter again. Still
no power. The car will not go more then 5 mph and
now overheats easily. The overheating is new. In the
meantime a slight power steering leak had become
a gusher. We just replaced the distributor, silent
days trying to get the timing set. Finally have it
running again, still no power. Have dumped nearly
$1000 in parts and labor and still at square one.
Help!!