I have a p0171 code for system to lean bank 1. I cleaned the MAF sensor and the permanent code went away but now popped up again as a normal code I don't know if I have bad o2 sensor or vacuums leak. I don't know how to tell if the o2 sensor is bad or if itfs a vacuums leak
My car has 97144 miles.
My car has an automatic transmission.
A number of things may cause code P0171 to be triggered. As the code indicates, this means there is a lean fuel condition which may be caused by a lack of fuel supply or in some cases, a vacuum leak. When a vacuum leak is present, this introduces an excessive amount of air into the fuel/air mixture which results in leaning out the fuel content. Other problems such as a faulty fuel pressure regulator, a faulty fuel pump, a clogged fuel filter, faulty fuel injectors, faulty oxygen sensors, or a faulty mass air flow sensor may also cause this to happen. I would suggest having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.
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