QX4 Check Engine light

[paulfromcbad]

My cousin owns a 200o QX4. The check engine light came on. they had it read, and it cae back with, P0171 Fuel System Lean, Bank 1. It was suggested in another section that i ask about the fuel filter. What else could fix this problem?

[Q45tech]

The only method ecu has to determine fuel codes is from O2 sensor waveforms....................delve deeper into diagnosis and you may find an old sluggish O2 sensor.

From google:"A code P0171 may mean that one or more of the following has happened:

The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters (K&N, etc.) can cause the MAF to become dirty if the filter is over-oiled There could be a vacuum leak downstream of the MAF sensor. Possible SolutionsPossible solutions include:

In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling Inspect all vacuum and PCV hoses, replace if necessary Check for a dirty fuel filter and proper fuel pressure "

READ this thread"zerothread/135082