"Running lean" engine fault

Hi
Recently bought a 2005 RR 4.4 V8 HSE now has143000 km's. It was running fine. Engine light cam on (amber, not flashing). Diagnosis gave a fault code (which I cant remember) and the description was "running lean on Bank 2". What is causing this fault? Is it major? I do long distances. Can it result in a break down? Is it fairly easy to fix?

Sihle (South Africa)

It depends on what is causing the engine to run lean. If it is just 1 bank that is affected, it may be a faulty Lambda sensor or blocked injector/s

Most likely components are lambda sensors as mentioned or an air leak in the bank 1 inlet tract.

Ideally get the car on real time diagnostics and observe the readings from the two oxygen sensors, they should be very similar.

Also compare the short term fuel trim on both banks, this will help you determine whether the engine is intentionally altering the mixture or not on bank 1.

Of course, as usual it could be a very simple find and fix of a complete pain in the arse to diagnose.