The NOC sensor adjust ignition timing to its most efficient level. It could cause this type of problem. I looked up the cost and labor. Dealer cost should be around 170.00 for the part and 2.9 hours labor to replace it. I don't know what their labor rate is, but it doesn't sound like they are too far off.
Now for potential other problems. It could be a vacuum leak allowing it to die at low RPM's, fuel pressure, crank sensor, ignition timing.
Before doing anything, make sure the ignition timing and idle speed are set correctly. Incorrect settings can cause driveability problems and false trouble codes. The timing, with a manual trans, should be between 13 and 16 degrees BTDC @ 575 to 675 RPM's. That is idleing in neutral. Check that and let me know if it is correct. I realize you set the idle speed but don't know if you checked timing. IF that is good, we'll move on to checking the crank sensor, coil, and fuel pressure.
Let me know what you find, and thanks for using 2carpros. Com.