The P0650 indicates there is a malfunction in the MIL control circuit. I don't feel that is related to the alternator.
Tell me. You indicated that you smell gas. If your scanner have a live data setting, let me know what the short term fuel trims are. Also, I know you replaced the catalytic converter already. The idea that you smell fuel may be indicating a rich issue and may have already damaged the new converter. Take a look through these links:
Now the link says to remove the converter. If you remove the oxygen sensor upstream from the converter, it will make a difference if the converter is once again plugged.
Also, are you certain there are no major engine vacuum related issues? Here is a link explaining how to check:
As far as the P0101, you are correct it is related to the MAF. However, it could be an electrical issue or even a vacuum leak causing a variation between the MAF and the manifold absolute pressure sensor (MAP). Here are directions related to the P0101. They explain the code, possible causes, and the pics attached below are diagnostic flow charts.
2002 Chevy Truck S10/T10 P/U 4WD V6-4.3L VIN W
Vehicle ALL Diagnostic Trouble Codes ( DTC ) Testing and Inspection P Code Charts P0101
The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal in order to provide the correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following circuits:
An ignition 1 voltage circuit
A ground circuit
A signal circuit
The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The frequency varies within a range of around 2,000 Hertz at idle to about 10,000 Hertz at maximum engine load. The PCM uses the following sensor inputs in order to calculate a predicted MAF value:
The manifold absolute pressure (MAP)
The intake air temperature (IAT)
The engine speed (RPM)
The PCM compares the actual MAF sensor frequency signal to the predicted MAF value. This comparison will determine if the signal is stuck based on a lack of variation, or is too low or too high for a given operating condition. DTC P0101 sets if the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value.
CONDITIONS FOR RUNNING THE DTC
DTCs P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0121, P0122, P0123, P0335, P0336, P0401, P0440, P0442, P0443, P0446, P0449, P1106, P1107, P1111, P1112, P1121, P1122, and P1441 are not set.
The engine is running.
The ignition 1 signal is between 11-18 volts.
The throttle position (TP) sensor angle is less than 95 percent.
The change in the TP sensor angle is less than 5 percent.
The MAP sensor is less than 80 kPa.
The change in the MAP sensor is less than 3 kPa.
The above conditions are met for 1.5 seconds.
CONDITIONS FOR SETTING THE DTC
The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 4.0 seconds.
Inspect for the following conditions:
An incorrectly routed harness. Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components:
- The secondary ignition wires or coils
- Any solenoids
- Any relays
- Any motors
The throttle plate for sticking, or for deposits on the throttle plate or in the throttle bore.
A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor.
A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor g/s display on the scan tool to increase rapidly. This increase should be from 6-12 g/s at idle to 130 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
The barometric pressure that is used in order to calculate the predicted mass air flow value is initially based on the MAP sensor at key ON. When the engine is running the MAP sensor value is continually updated near wide open throttle. A skewed MAP sensor will cause the calculated mass air flow value to be inaccurate. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude.
A high resistance on the ground circuit of the MAP sensor may cause this DTC to set.
Any loss of vacuum to the MAP sensor may cause this DTC to set.
A high resistance in the ignition voltage circuit of the MAF sensor may cause this DTC to set.
If you suspect the condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Diagnostic Aids.
If the condition is intermittent, refer to Intermittent Conditions. See: Computers and Control Systems > Initial Inspection and Diagnostic Overview > Intermittent Conditions
The numbers below refer to the step numbers on the diagnostic table.
4. This step will determine if the MAP sensor voltage is within the proper range at idle.
5. This step will determine if the MAP sensor responds properly to the change in manifold pressure.
6. This step will determine if the throttle position (TP) sensor is operating properly.
7. This step will determine if any mechanical faults have caused this DTC to set.
Let me know if any of this helps or if you have other questions.
Images (Click to enlarge)
Monday, December 14th, 2020 AT 9:08 AM