2004 envoy service engine light stays on. Told

P0172 LEXUS - System Too Rich Bank 1
Possible causes
Faulty front heated oxygen sensor
Ignition misfiring
Faulty fuel injectors
Exhaust gas leaks
Incorrect fuel pressure
Faulty Mass Air Flow (MAF) sensor
https://www.autocodes.com/p0172_lexus.html

http://www.obd-codes.com/p0410

All those codes and such an easy fix. ALL of these codes point to your upstream 02 sensor. It's the one on the passenger side of the engine coming off the exhaust, very very easy to get to. Soak that puppy with PB Blaster then remove the electrical connector and remove and replace sensor. TRY to stay away from Bosch 02 sensors, have been known and reported problems with these. In my case, I didn't have a choice but to buy the Bosch, but I haven't had any problems with mine.

Hope this helps, look to get a tad more miles per gallon too.

www.engine-light-help.com/generic-checki-engine-light-codes.html

p0410 code pos causes loose or broken hose on smog pump or bad check valve on exhaust man were smog hose atatches

Trouble Code: P0410 (4.2L L6 VIN S Auto)
HO2S 1 Insufficient Response Print this code data Number of Trips to Set Code: 1
OBD II Monitor Type: CCM Details
Indicators: MIL Details

• CCM Details

Trouble Code Conditions:

• DTCs P0105, P0107, P0108, P0112, P0113, P0122, P0123, P0130, P0131, P0132, P0133, P0134, P0171, P0172, P0300, P0301-P0304, P0341, P0506, P0507, P0601, P0602 are not set.
  
• The AIR system is commanded ON for more than 20 seconds.
  
• The IAT is between 1-151°C (32-302°F).
  
• The engine coolant temperature (ECT) is between 5-114°C (41-230°F).
  
• The start up ECT is between 3-50°C (37-122°F).
  
• The battery voltage is more than 11 volts.
  
• The engine run time is more than 200 seconds.
  
• The vehicle is operating in fuel trim cells 16 or 17.
  
• The throttle position (TP) change is less than 5 percent.
  
• The manifold absolute pressure (MAP) is less than 30 kPa.
  
• The engine speed is more than 1,150 RPM.
  

Possible Causes:

• An intermittent may be caused by any of the following conditions:
  
  • Low system airflow
    
  • Excessive exhaust system back-pressure
    
  • Pinched, restricted, split, or damaged pipes/hoses
    
  • Restrictions in the AIR pump inlet hose
    
  • Pitted contacts in the AIR pump relay, AIR solenoid relay--Tap on the AIR pump relay or AIR solenoid relay to attempt to duplicate an intermittent condition.
    
  • Heat damage to the AIR outlet hose may indicate an shut-off valve failure
    
  • Yellow tinted water in the AIR pump may indicate an shut-off valve failure
    
  • Water or debris ingested into the AIR pump
    
  • Observe the Freeze Frame/Failure Records to aid in conditions of setting DTC P0410
    

The link below explains it well. And pay attention to the notes about checking if this is covered under your emissions warranty!

http://www.obd-codes.com/p0410

Track the p0340 first camshaft timing is very important and could possibly cayse your other codes,Call your local GMC dealer I think I remember a bulletin about this code.

most ecu controlled vehicles have a 'limp home'mode if 2 or more fault codes are stored,it is designed to get your attention before damage is caused and to get you to the nearest w.shop to fix,i would have codes cleared and retest vehicle,it is the cheapest and 1st option for any shop,some late models even have excessive mileage past service interval in the 'limp' program

 P1107 MAP Sensor Circuit Intermittent Low Voltage 
P1410 Fuel Tank Pressure System
Good luck and hope this helps