it's a generic fuel trim malfunction - lean on bank 1
vac leak could cause it took
this is off of an obd2 site tho
Causes
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 Solutions
Possible 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 <LI nd="9">Inspect all vacuum and PCV hoses, replace if necessary
- Check for a dirty fuel filter and proper fuel pressure