2003 Pontiac Sunfire • 180,000 miles

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?
February 11, 2013.

Has PCM ben scanned for codes? When it acts up does MIL come on? Why where all the parts replaced?

Feb 11, 2013.
PCM was scanned, no codes were present. Please reference what the MIL is? Part were replaced because all indication was that the IAC module was causing it. After that, the two other sensors were replace to attemt to fix the problem. Could the PCM be Faulty?

Feb 12, 2013.
MIL check engine light PCM maybe would need a diagnostic scan tool hooked up in Drive mode to monitor what sensors are inputing to PCM and what PCM is doing to control fuel mix, timing ect

Feb 12, 2013.