Erratic idle/engine

I have a 2000 Contour SE with a 2.0 engine, bought with 100K two years ago. The engine runs erratic, sometimes stalls with no codes. The following items have been replaced: fuel filter, plugs, wires, IAC and MAF (Motorcraft). The fuel rail and injectors were removed and cleaned. When the IAC engages the rpms jumps and then almost stalls. This problem is not constant. I disconnected the vacuum line on the fuel pressure sensor (regulator?) at the end of the fuel rail, no change in idle. I disconnected the IAC, the engine died. I removed the air intake tube and the engine runs slightly better and does not stall. Of course the P0118 code comes right up. I do not know if this is a vacuum leak problem, an IAC problem, or other (EGR, PCV). I see many idle/run problems but never a common solution. Any help would be appreciated.