2000 silverado 1500 4.8 bank 1 and bank 2 to lean how can i fix

System too lean, bank 1.

EOBD II Error Code: 25
Description:
System too Lean, Bank 1
Possible Causes:
- Intake/exhaust leak.
- Secondary air injection (AIR) system.
- Manifold absolute pressure (MAP) sensor.
- Mass air flow (MAF) sensor.
- Fuel pressure/pump.
- Injector(s).
- Evaporation emission (EVAP) canister purge valve.
- Heated oxygen sensor (HO2S).
- Contaminated fuel.

EOBD II Error Code: 26
Fault Location:
System too Rich, Bank 1
Description:
- Evaporation emission (EVAP) canister purge valve .
- Fuel pressure.
- Injector(s).
- Heated oxygen sensor (HO2S).
- Contaminated fuel.
Hope that works.

It is a generic OBD2 power train Code. The same solution could be applied to all other vehicles as well.
Error Code: P0171
Description:
Fuel Trim (FT), System too Lean, Bank 1
Possible Causes:
- Fuel pump pressure too high or regulating valve stuck closed.
- Intake/ exhaust leak.
- Secondary air injection (AIR) system.
- Manifold absolute pressure (MAP) sensor.
- Mass air flow (MAF) sensor.
- Fuel pressure/pump.
- Fuel Injector(s).
- Evaporative emission (EVAP) canister purge valve.
- Heated oxygen sensor (HO2S).
Solutions:
-Usually, simply cleaning the Mass air flow (MAF) sensor helps solve the problem.
- It is best to take MAF off and spray it with electronics cleaner or high flash point solvent.
- Inspect all vacuum and PCV hoses, replace if necessary.
- Check for a dirty fuel filter and proper fuel pressure.

P0171 - System Too Lean (Bank 1)

Basically this means that an oxygen sensor in bank 1 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1.

Note: This DTC is very similar to P0174, and in fact your vehicle may show both codes at the same time.

Symptoms: You will more than likely not notice any drivability problems, although there may be symptoms such as a lack of power, detonation (spark knock), and/or a hesitation/surge on acceleration.


Causes: A code P0171 may mean that one or more of the following has happened:
* The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
* There could be a vacuum leak downstream of the MAF sensor.


Possible solutions include:
* In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
* Inspect all vacuum and PCV hoses, replace if necessary
* Check for a dirty fuel filter and proper fuel pressure


Hope helps.

P0174 Generic Definition

Fuel Trim Bank Two Condition
- The ECM has detected a rich or lean air/fuel ratio condition on engine bank two

Probable Cause[s]

1. If bank one and two are set together suspect a fuel pressure condition or MAF sensor fault
2. Failed HO2S21
3. Ignition misfire condition
4. Fuel injector problem
5. Engine mechanical condition

P0171 Generic Definition

Fuel trim bank one condition
- The powertrain control module uses the oxygen sensor to calculate the air/fuel ratio of the engine. The computer has recognized a rich or lean condition on one engine bank only.

Probable Cause[s]

1. If bank one and two codes set together suspect fuel pressure or MAF (Mass Air Flow) Sensor
2. Oxygen sensor defective
3. Ignition misfire-repair
4. Fuel injector problem

lean on bank 1 and bank2 lean do you have cadiclic converters no truck have you changed o2 sensor or what have you done

besides the heated oxygen sensors being faulty, lean mixture codes also refer to intake/exhaust leaks ( cracked flex section of exhaust pipe at manifold , low fuel pressures /pump, faulty injectors , MAF/VAF,wiring and ECM

Basically this means that an oxygen sensor in bank 2 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 2 is generally the side of the engine that doesn't have cylinder #1.

A code P0174 may mean that one or more of the following has happened:

•The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters can cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
•There could be a vacuum leak downstream of the MAF sensor.

Possible solutions include:

•In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for its location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
•Inspect all vacuum and PCV hoses, replace if necessary
•Check for a dirty fuel filter and proper fuel pressure

vacuum leek,bad computer or you have a linkage out of adjustment on the throttle body