P0171 NISSAN - how do i eliminate causes?

Question

2001 Nissan Pathfinder 3.5 ltr v-6 4x4. Code Po171 has many possible causes. How can i eliminate without replacing all items (ex[ensive)

Answer 1

You could start by doing the inspection listed on the possible causes,  there is nothing to buy for that. Inspect for air intake and exhaust leaks. and inspect the air filter. Replaced the air filter if is dirty. If all that check, then try erasing the code, if the codes come back and there are not driveability problems, you may have to replace the O2 sensor to fix the problem. IO you have some engine performance problem or the engine is running rough, the you may need to replace the mass air flow meter.