Changed IAC Valve?
Looks like a can
None of those changes would probably help with those symptoms, with the exception of fuel filter and maybe fuel pump.
Sensors rarely fail, but are often replaced, lol
Assuming you have run Seafoam or similar injector cleaner thru the system since it has been sitting, or put in new injectors, it reads like exhaust could be clogged.
(dirty injectors would have limited flow at higher demand)
Vacuum gauge is still the best way to test for an engine problem, can tell you alot about any gasoline engine, and at $25 not an expensive tool
Good read here on the test to do:
http://www.gregsengine.com/using-a-vacuum-gauge.html
No matter what "they" add to the outside of a gasoline engine it is still just a self-powered air pump, and no better way to test a pump than by reading its pressure, in this case negative pressure, vacuum pressure
Symptom of losing power as load/RPM increases could be back pressure is building up in the exhaust system, you could have someone increase engine RPMs while you feel tailpipe exhaust flow, it should of course increase as RPMs increase, if it levels off then you have a partial blockage.
I would also change the O2 sensor on spec, these use a chemical reaction to measure oxygen in the exhaust, so they do wear out just like a battery, chemical gets used up even sitting, recommended change is at 100k miles, so not a haphazard sensor change
But O2 sensor is not your problem
