For a 2006 Toyota Corolla, what is the most common fix for a P0171 code?

Question

I have cleaned the air mass flow sensor, changed the fron o2 sensor about 6 months ago, along with the camshaft location sensor. Air filter has about 500 miles on it, and is still clean.

Answer 1

P0171 Fuel system trim lean.

Common cause,MAF,vacuum leaks,fuel pressure (low volume) How is the sparkplugs a worn sparkplug can and will cause P0171.You are equipt with a COP (coil on plug) in the sparkplug chamber the valve cover tends to leak oil into the sparkplug chamber and this can cause a lean condition. A carbon up throttle body can cause this code,this is where a throttle body cleaning can help. This code can also appear when you are running out of fuel.