I need the plastic tube between the airflow meter and the intake

Check for vac leak or ripped air intake tube or mass airflow meter

Well, the mass airflow meter and sensor should be the same part.
Its a metal (plastic) tube between the intake and the air filter with a sensor inside. They are available new and rebuilt.

I don't know the term flow mix sensor but running lean bank 1 & 2 sounds like oxygen sensors in the exhaust as they are reading how well your engine is burning the air fuel mixture going into your engine. But I would 1st look for a split or loose clamp on your intake tube after the airflow meter as this will allow more air into the engine than is being metered my the airflow sensor causeing it to run lean.

When you unplug the mass airflow sensor, the car goes into "limp home" mode in which it runs full rich. Generally speaking, if a car runs better with the mass airflow sensor unplugged than with it plugged in, the mass airflow sensor has failed.
However, the drifting idle tends to make me want to look for vacuum leaks and check the rear temperature sensor on the driver side of the head. I suspect that running over-rich is compensating for the vacuum leak so the car keeps running.
If you have a propane torch or a can of diesel starting ether, spray it around the intake manifold while the car is idling and see if the engine speeds up. If so, then you have found a vacuum leak.
If it were mine, I would buy a new intake manifold gasket and replace it as a routine maintenance item. It is not expensive or difficult to replace except that if you are like me, you WILL drop at least one nut, and there are several great hiding places on that side of the engine where the nuts go to hide when you drop them. You will need a magnet to recover them. You don't need to pull the manifold clear off, you just have to pull it clear of the bolts so you can slip in a new gasket. You can leave the throttle cables and most of the other connections hooked up
If you know how to use an ohm meter, you might consider getting a manual for this car and looking up the appropriate resistance/temperature values and checking that rear temperature sensor.
While you are replacing that intake manifold gasket, check all the vacuum ports to make sure they are clear, and check all the vacuum hoses to make sure they are intact. Also check the tubes between the mass airflow sensor and the throttle body for cracks. While you have those air tubes off, clean the throttle body and the idle air control valve with some carb cleaner. Spray a little carb cleaner through the mass airflow sensor as well. Actually, there is a special spray for cleaning mass airflow sensors that is more gentle, but I have used carb cleaner on them many times with no apparent ill effects.
If it turns out that the mass airflow sensor has failed, that will run some $$, but having a fresh intake manifold gasket and clean throttle body and no vacuum leaks will be worth your time and money and make the car run better when you are done.

You may want to check the air flow meter, if it is dirty that can cause that issue.
the air flow meter can get contanimated by inlet air environment and Wet air filter oil, the airflow meter is the sensor in the intake hose and is very fragile, it can be cleaned by airflow sensor cleaner or break clean and letting air dry. Try that, or take to local honda dealer, you never know if there is an update to the ECU and they know the vehicles very well.

The Sentra is known to blow mass airflow sensors. If you bought an aftermarket sensor and it says to reprogram the computer you are pretty much out of luck. If it were me I would read the instructions again as it probably means that you have to disconnect the battery for five minutes and let the computer learn the new mass airflow sensor.

The mass airflow sensor, or MAF sensor, measures the amount of air flowing into the engine through the air intake. The sensor on your Nissan Sentra is located in the air intake tubing that runs from the filter to the fuel injection system. If your Sentra is idling rough, has problems starting and frequently stalls during normal driving, it is likely that the MAF sensor is failing and needs to be replaced.

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Things You'll Need:

• Socket wrench and socket set Screwdrivers (Philips and slotted) New MAF sensor

Instructions

1. Open the hood and locate the air box. It should be on the passenger side of the engine bay near the front of the vehicle. It will be a plastic, box-shaped object with a large plastic pipe running to the back of the engine.
   
2. Examine the new MAF sensor. You'll be looking for this component in the air box.
   
3. Remove the air box cover and pull the air filter out.
   
4. Loosen the band clamps on the intake tubing with a screwdriver and pull the intake tubing off of the air box.
   
5. Unplug the electrical connection to the MAF sensor and pull the MAF sensor out of the air tube assembly.
   
6. Install the new mass airflow sensor and put the air box assembly back together. Installation is the reverse of removal.
   

Hope this help to solve your problem (remember comment and rated this).

the airflow sensor is the box like item on the airbox tubing b4 the airbox its self there should be a solid plastic tobe/pipe between 2 rubber 1s with a wiring plug attached this is the airflow meter/sensor

If it has one it will be in-line of the tube (air intake) that goes to intake manifold. Or it might not have a mass airflow sensor and have a map sensor instead.

You MUST have the air flow meter installed on your vehicle. The car will not run if you remove it. The Air Flow Meter measures the amount of air coming into the engine, and also the air temperature. This information is sent to the fuel injection computer, to determine the proper fuel to be injected. In reality, cars with "air-flow meters" do not really "benefit" from a cold air intake, due to the inherent restriction that the air flow meter causes, as it measures the air.
In short, I would not install the intake, you won't see much benefit. The graciousness of a FixYa rating for my assistance would be greatly appreciated..

Its in your intake by the air filter. Remove the intake tube and there are a couple of bolts holding the sensor in place Its the only hard plastic unit in line with your intake. Disconnect battery for safety. Any questions just ask.