Several things can cause this:
* Vacuum Leaks: A significant vacuum leak in the intake system on Bank 2 will allow excess air to enter, leading to a lean condition. This is a common cause. Look for cracks in hoses, loose connections, or failing gaskets.
* Mass Airflow Sensor (MAF) Issues: A faulty MAF sensor can provide inaccurate readings to the engine computer, resulting in an incorrect air/fuel ratio. A dirty MAF sensor can also cause this problem.
* Fuel Injectors: Clogged or malfunctioning fuel injectors on Bank 2 could prevent sufficient fuel from being delivered.
* Fuel Pump: A weak or failing fuel pump might not provide enough fuel pressure, leading to a lean condition.
* Fuel Filter: A clogged fuel filter can restrict fuel flow.
* Oxygen Sensor (O2 Sensor): A malfunctioning O2 sensor on Bank 2 might give incorrect readings to the engine computer, influencing the fuel mixture.
* EGR Valve: Problems with the Exhaust Gas Recirculation valve can affect the air/fuel mixture, though less likely to be a primary cause of P0174.
Troubleshooting Steps:
1. Check for Vacuum Leaks: Visually inspect all vacuum hoses and connections on Bank 2. Listen for hissing sounds with the engine running. Use a propane torch (carefully!) to check for air leaks near the intake manifold.
2. Clean the MAF Sensor: Carefully clean the MAF sensor with MAF sensor cleaner (never use anything else).
3. Check Fuel Pressure: A mechanic will need to test the fuel pressure to see if it's within specifications.
4. Inspect Fuel Injectors: This often requires specialized tools and may be best left to a mechanic.
5. Inspect Fuel Filter: Replace the fuel filter as a preventative measure if it's old.
6. Check O2 Sensor: While less likely to be the sole cause of a P0174, a failing O2 sensor can contribute to the problem.
It's crucial to diagnose the root cause rather than just addressing the code. Ignoring this could lead to engine damage. A mechanic with a scan tool and diagnostic equipment can accurately pinpoint the source of the problem. Don't just replace parts randomly; that's expensive and ineffective.
