Monitors will not clear?

If the engine never gets up to operating temperature the computer will not go into closed loop which will cause the monitors not to set. I would remove the thermostat to see if it is stuck open. If you have a temperature gauge, have you noticed the needle is down on the cold side? Here is the location and how to change it out in case you want to do the inspection. Check out the images (below). Please upload pictures or videos of the problem so we can see what's going on.

What scan tool do you have? GMs will not run the CAT tests if certain thresholds are not met
This is the OE drive cycle - Note the time between drive cycles and the tests highlighted for EVAP and CAT. Those and fuel level are common failure points. On them.

INSPECTION/MAINTENANCE (I/M) COMPLETE SYSTEM SET PROCEDURE

IMPORTANT: Always perform the Inspection/Maintenance (I/M) System Check prior to using this diagnostic procedure

DESCRIPTION
The purpose of the Inspection/Maintenance (I/M) complete system set procedure is to satisfy the enable criteria necessary to execute all of the I/M readiness diagnostics and complete the trips for those particular diagnostics. When all I/M monitored diagnostic tests are completed, the I/M System Status indicators are set to YES. Perform the Inspection/Maintenance (I/M) Complete System Set Procedure if any I/M System Status indicators are set to NO.

CONDITIONS FOR MEETING A COLD START
- The ignition voltage between 11.0 and 18.0 volts.
- The barometric pressure (BARO) is more than 75 kPa.
- The start-up engine coolant temperature (ECT) is between 4-30°C (39-86°F).
- The start-up intake air temperature (IAT) is between 4-30°C (39-86°F).
- The difference between the IAT and the ECT is 6°C (10.8°F)
- The ambient air temperature is between 4-30°C (39-86°F).
- Fuel level is between 15-85 percent
- Vehicle has NOT been refueled since the last cold start ignition cycle.

CIRCUIT/SYSTEM VERIFICATION
Review the Inspection/Maintenance (I/M) System Status indicators. All I/M System Status indicators should report YES.

INSPECTION/MAINTENANCE (I/M) SYSTEM SET PROCEDURE
1. Ensure that the vehicle meets the conditions for a cold start listed above.
- If the EVAP I/M System Status indicator displays NO, perform the EVAP Service bay test if applicable.
- If the EVAP Service bay test is NOT available, it may take up to 6 drive cycles, with 17 hours between drive cycles for the EVAP I/M System Status Indicator to transition to YES.
- If the O2S Heater System Status indicator displays NO, ensure that the ignition has been turned OFF for at least 10 hours.

IMPORTANT- Whenever the ignition is turned ON, ignition positive voltage is supplied to the heated oxygen sensor (HO2S) heaters. After verifying the enable criteria, turn OFF the ignition for approximately 5 minutes to allow the sensors to cool before continuing with the test. Once the engine is started, do NOT turn the engine OFF for the remaining portion of the set procedure.

2. Turn OFF all accessories; HVAC system, other electrical loads, including aftermarket/add-on equipment, etc, and open the hood.
3. Set the vehicle parking brake and ensure the vehicle is in park for automatic transmission or neutral for manual transmission.
4. Turn the ignition ON with the engine OFF for 1 minute.
5. Start and idle the engine for 2 minutes and until 65°C (149°F) is achieved.
6. Run the engine for 6.5 minutes within the following conditions:
- MAF parameter between 4-30 g/s
- Engine speed steady between 1000-3000 RPM
7. Return the engine to idle for 1 minute.
8. Apply and hold brake pedal, and shift to Drive for automatic, or apply clutch pedal for manual and operate the vehicle within the following conditions for 2 minutes:
- Depress the accelerator pedal until TP Sensor angle is more than 2 percent.
- MAF signal between 15-30 g/s
- RPM steady between 1200-2000 RPM
9. Release the accelerator pedal and shift the vehicle to Park for automatic, or Neutral and release clutch pedal for manual, and allow the engine to idle for 2 minutes.

IMPORTANT- Do NOT touch the accelerator pedal until told to do so. A change in TP Sensor angle or an increase in engine speed may invalidate this portion of the test.

10. Quickly depress the accelerator pedal until TP Sensor Angle is more than 8 percent and return to idle, repeat 3 times.
11. Allow engine to idle for at least 2 minutes.
12. Close the hood, release the parking brake and drive vehicle at 24 km/h (15 mph) or slower for 2 minutes.

Refer to Road Test Caution.

13. Continue to drive the vehicle for at least 5.5 miles between 45-112 km/h (28-70 mph) with the vehicle reaching at least 80 km/h (50 mph).
14. Release the accelerator pedal for at least 3 seconds. This will allow the vehicle to enter the decel fuel cut off.
15. Depress the accelerator pedal until the TP Sensor angle is between 3-20 percent and maintain for 1 minute.
16. Safely stop the vehicle, with the engine in drive for automatic or neutral with the clutch pedal depressed and parking brake applied for manual. Allow the vehicle to idle for 2 minutes.
17. Shift the vehicle to park for automatic and neutral for manual. Turn OFF the ignition and exit the vehicle. Do NOT disturb the vehicle for 45 minutes.

IMPORTANT- Do NOT disturb the vehicle or turn ON the ignition until told to do so. Disturbing the vehicle may invalidate this portion of the test.

18. Observe the Inspection/Maintenance (I/M) System Status with a scan tool. All of the I/M System Status indicators should display YES.
- If the EVAP I/M System Status indicator displays NO turn OFF the ignition for 17 hours, ensure that the vehicle meets the conditions for a cold start, and repeat steps 13-18 three more times, or until the EVAP I/M System Status indicator transitions to YES. If the indicator continues to display NO, refer to the Inspection/Maintenance (I/M) System DTC Table to identify the DTCs that did not run.
- If any of the I/M System Status indicators display NO, refer to the Inspection/Maintenance (I/M) System DTC Table for the indicator which did not display YES. The I/M System DTC Table identifies the DTCs associated with each I/M System Status Indicator.

The EVAP service bay test doesn't require the truck be in the air that I recall.
SERVICE BAY TEST

DESCRIPTION
The evaporative emission (EVAP) Service Bay Test raises the engine coolant temperature (ECT) threshold so that the temperature sensitive EVAP diagnosis tests can run while in service environments. When the EVAP tests are run the service bay test will indicate a pass or will indicate a specific DTC has failed. The EVAP service bay test can be used to verify an existing condition and verify that the EVAP system is OK after a repair is completed.

CONDITIONS FOR RUNNING THE TEST

IMPORTANT: The following conditions must be met in order to enable the Service Bay Test:
- The ignition is ON.
- The battery voltage is between 9-18 volts.
- The engine coolant temperature (ECT) is less than 70°C (158°F).
- The fuel level is 15-85 percent of capacity.
- The vehicle speed is less than 4.8 km/h (3 mph).
- Stored DTCs have been cleared.

TEST PROCEDURE
1. Install a scan tool.
2. With a scan tool, select the service bay test in the special functions menu.
3. Follow the instructions on the scan tool.
4. Check DTCs with a scan tool.
5. Continue with the published service data diagnostic DTC procedure.

Yes, you need to add fuel for it to run the EVAP test. The service bay test shows that the EVAP can pass, but it doesn't record that in the ECU, it has to run the drive cycle and pass for that. Don't see the report but it sounds like the converter monitor is still not set?

Yes, being in NY myself I'm very familiar with the inspection process. At least you are trying to be legal, I get folks all the time wanting ways to avoid the laws. Nope, not getting hit with the fine and possibly being closed down because someone decided to straight pipe their car.

Yes, you need to add fuel for it to run the EVAP test. I try to run it at 1/2 tank as it meets the requirements and can avoid things like bad senders at low levels. Unfortunately, yes you need to wait, but I've had some shock me and clear right after I added fuel.

We try to keep issues separated to make searches easier. As such I'll ask you to put those up as new questions. That way if someone else is looking for a similar problem it will show up.

That is the drive cycle for all monitors. It should set them all to complete as long as there are no codes, and the conditions are met.