P0171 code does indeed indicate system too lean (bank 1). The O2 sensor nearest the engine on the exhaust is the bank 1 sensor. Here is a list of the many things that can cause this.


Air induction system

Injector blockage

Mass air flow meter

Engine coolant temp. sensor

Fuel pressure

Open or short in A/F sensor (bank 1 sensor 1) circuit

A/F sensor (bank 1 sensor 1)

PCV valve and hose

PCV hose connection

EFI main relay

A/F sensor heater and relay circuit

But don't forget to think simple first. The code says it is running lean...so did you run it out of gas recently? When was the fuel filter changed last? Check it real good for bad or disconnected vaccum lines to include the PCV valve and hose. Check your air induction system for leaks allowing air to enter after the Mass Air Flow Meter. Any in depth trouble shooting requires the shop manual and an OBDII computer or at least a multimeter that reads in mili-volts. Good luck with it, let us know if ya have any other questions.