2001 Nissan Sentra engine surging

Inspect and test all the following listed below:

Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
False air leakage.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note:If it doesn't apply disregard.

I dont have a 2001, I have a1997, but I had the same problem, and it was ridiculously simple. My engine would idle normally when i started it, but if I stepped on the accelerator, it would keep giving gas like if if I was driving even if i put it in park. Nobody knew what was wrong with it, and kept telling me to replace these ridiculously expensive things. The idle air control valve on foreign cars rarely goes bad, but nissans are not the cleanest burning things. The IAC can become clogged, and get stuck in the open position. Its attached to the top of the throttle body. Unscrew it, and clean the metal piece on the head with some carburator cleaner. When its dry, reattach it. It should stop sticking.