Acceleration malfunction AFTER $600 in repairs

The problem is that the car will no go over a certain amount of Revs. I can never seem to get the revs above 4000 without the engine choking, and this amount constantly decreases as the car gets hotter. The hotter it gets, the less revs, meaning I have to stop and wait a good 20-30 minutes every 30 miles or so.

Multiple repairs have been done, and now the on-board engine checking system has proved useless.

OBD2 Readouts:

Issue 1: Idle Air Control Valve Malfunction (Plunger stuck open)
Solution: IAC Valve replaced completely, did not clear code. (Aftermarket BWD)

Issue 1.1: Mechanic suggested EGR valve may be faulty and causing IAC valve to stay open.
Solution: EGR Valve replaced completely, code cleared. (Aftermarket BWD)

Issue 2: IMRC Valve Stuck Open
Solution: Completely replaced IMRC directly from Ford, code cleared.

Issue 3: O2 Sensor circuit malfunction, Bank 1 Sensor 1; O2 Sensor circuit malfunction, Bank 2 Sensor 1.
Solution: Both sensors replaced with Bosch aftermarket sensors, codes cleared.

Parts Total: Roughly $600

I had figured that after doing all of this, the engine would run okay, but the problem remains. I cannot accelerate effectively, which is making it very dangerous to pull onto roadways and highways, nor can I get anywhere further than 20 or 30 miles away in a short amount of time.

The engine is no longer giving codes, but it still having issues. I prefer to do these things myself, but I'm getting to the point where I may have to bring it to a mechanic, and practically shower him with money.

My current theory, after doing a lot of research on ford repairs forums, is that there is a problem with the Catalytic converters, which is dreadful to me considering how expensive they are.