An engine runs by the combustion of a mixture of oxygen and gasoline. If this mix has too much oxygen, it is said to run lean. When the mixture has too much gasoline in relation to oxygen, it is running rich.
It could do. DOn't let it run lean. It's very uneconomical and bad for the engine.
It means the Fuel/Air mixture is not correct. Too lean means the mixture has too much air and not enough fuel. If the engine idles rough but runs good under acceleration, suspect a leaking vacuum hose. If the engine runs perfectly suspect a defective MAF sensor.
P0171 System too Lean (Bank 1)
Cars running lean
Could be sucking air into intake.
This might be from unproper jetting of the carb. It is most likely running to lean,this is why the pipe has turned yellow.When and engine runs lean it tends to run hotter
to lean = nish'an (נשען)
Fuel system running lean.
Trouble code P0171 means:System too lean (Bank 1)
Lean Mean Thirteen has 486 pages.
There could be several symptoms such as lack of power, engine idles but won't rev up, check engine code(s) about lean conditions or random misfire and with a totally clogged fuel filter the engine won't run at all.