Nissan Repair: 1990 Maxima stalling, haynes manual, air meter

Question
I have a 90 Maxima with approximately 240,000 miles on it.  I have owned the car for about a year.  Overall, the car runs well.  In the last couple of months, I have started to have problems with the car stalling. It does not happen when the car is not warmed up. The tachometer with no warning will drop to 0rpm's. The car will almost come to a complete stop almost immediately.  If I am in a lower gear and push the clutch in and release it quickly, it will sometimes start.  Sometimes it will lunge forward without the clutch being pushed in like nothing ever happened.  It doesn't happen everytime I drive the car, but a good percentage of the time.  It always seems to restart.  It may go 2 inches and stall again or not at all.  It seems to happen more frequently as I get lower on gas, but will still happen even with a full tank.  I have replaced the fuel filter, and that didn't change anything.  I have run fuel injector cleaner through 3 full tanks.  It seems to stall out easier if I am going up a hill, but is not guaranteed to stall everytime.  I really like this car, but I don't want to keep guessing at things that may be wrong.  Any help would be appreciated or if I have not given enough information, I will answer anything you might want to know.  Thank-you.

Answer
Sandy,

Get a Haynes Manual and it shows how to check for codes.  To me it sounds like the air meter is going out or the distributor is contaminated with oil.  Run the codes and email me back. Here is how to read the codes, but still purchase the book as it is very helpful and, at $20 bucks, is much cheaper than the factory service manual.  
The ECU has a window on one side to view a red LED and a green LED - when checking fault codes, a red flash is worth 10, and a green flash is worth 1. So for example, the code to say that everything is functioning normally would be 5 red flashes and 5 green flashes - the code is 55.

The ECU has 5 modes of operation, for diagnostics codes, it has to be set to mode 3.

1. Make sure the screw next to the viewing window is turned clockwise.
2. Turn the ignition on
3. Both LEDs with flash once, then a pause, then a second time, then a pause, etc. etc. up to 5 times then will repeat the process. After is has flashed 3 times then turn the screw completely anti-clockwise. - this will select mode 3.
4. The LEDs will now flash codes. 55 means that everything is normal. The rest are written below.
5. When finished, turn the screw back to clockwise and the ECU will reset itself automatically.

Don't worry about the '5th cylinder misfire' and '6th cylinder misfire' or anything, the codes are the same for all Nissans.
11 Crank Angle Sensor/Camshaft Position Sensor.
12 Air Flow Meter/Mass Air Flow Sensor.
13 Engine Coolant Temperature Sensor.
14 Vehicle Speed Sensor.
21 Ignition Signal.
22 Fuel Pump.
23 Idle Switch.
24 Throttle Valve Switch.
25 Idle Speed Control Valve.
28 Cooling Fan Circuit.
31 ECM.
32 EGR Function.
33 Heated Oxygen Sensor.
34 Knock Sensor.
35 Exhaust Gas Temperature Sensor.
36 EGR Control-Back Pressure Transducer.
37 Knock Sensor.
38 Right hand bank Closed Loop (B2).
41 Intake Air Temperature Sensor.
42 Fuel Temperature Sensor.
43 Throttle Position Sensor.
45 Injector Leak.
47 Crankshaft Position Sensor.
51 Injector Circuit.
53 Oxygen Sensor.
54 A/T Control.
55 No Malfunction.
63 No. 6 Cylinder Misfire.
64 No. 5 Cylinder Misfire.
65 No. 4 Cylinder Misfire.
66 No. 3 Cylinder Misfire.
67 No. 2 Cylinder Misfire.
68 No. 1 Cylinder Misfire.
71 Random Misfire.
72 TWC Function right hand bank.
73 TWC Function right hand bank.
76 Fuel Injection System Function right hand bank.
77 Rear Heated Oxygen Sensor Circuit.
82 Crankshaft Position Sensor.
84 A/T Diagnosis Communication Line.
85 VTC Solenoid Valve Circuit.
86 Fuel Injection System Function right hand bank.
87 Canister Control Solenoid Valve Circuit.
91 Front Heated Oxygen Sensor Heater Circuit right hand bank.
94 TCC Solenoid Valve.
95 Crankshaft Position Sensor.
98 Engine Coolant Temperature Sensor.
101 Front Heated Oxygen Sensor Heater Circuit right hand bank.
103 Park/Neutral Position Switch Circuit.
105 EGR and EGR Canister Control Solenoid Valve Circuit.
108 Canister Purge Control Valve Circuit