Car is surging and stalling

Car is surging and stalling. Problem is speratic and works fine otherwise. Changed MAP, IAC, TPS and Air Intake Sensors. Cleaned Throttle Body and AIC intake port. Changes Fuel Filter. Still have same problem. Doing some research, possible solutions I found so far are: Check fuel pressure, Change Mass Air Flow sensor ( may be the sensor I changed that the dealer called the Air intake sensor on the air intake assemply between Air filter and Throttle Body), reflash the PCM (did have a factory radio replaced just before problem began and dealer had to program it for the radio to work, this is a theft control procedure), Plug on AC relay could be faulty and causing the computer to be confused and causing the engine to rev. Any advice?