I have replaced Fuel Filter, Air Filter, MAF Sensor, New PLUGS, THERMOSTAT, WITH OLD MAF SENSOR HESITATES ON ACCLERATION, POOR GAS MILEAGE MAYBE 250 MILE PPER TANK, WITH NEW MAF SENSOR MISSES AT IDLE GETS A LITTLE BETTER HAS IT WARMS UP, HAD INJECTORS CLEANED, I USE TO GET 400 MILES PER TANK, DON, T KNOW WHAT ELSE TO TRY? MAYBE FUEL PUMP, EGR VALVE, PVC NO LEAKS, INTAKE MANIFOLD NO VACCUUM LEAKS, HELP PLEASE
Also has new o2 sensors, It has a 2.0 16 valve Ztech motor
September, 22, 2012 AT 8:59 AM
These are what can cause a P0171
HO2S and sensor connection.
Fuel injector and/or fuel injector circuitry.
Powertrain Control Module (PCM).
Electrical circuits (HO2S, HO2S GND, INJ 1-8, VPWR and SIG RTN).
To prevent replacement of good components, be aware the following non-EEC areas may be cause of driveability concerns: Ignition system.
Faulty evaporative emission system.
EGR and/or PCV system.
Air intake system.
Engine oil contamination.
Exhaust system leaks or restriction.
Engine cooling system.