Keep getting error code PO171

WAYNEWEATHERMAN

MEMBER
1996 FORD CONTOUR
160,000 MILES

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

3 Replies

KHLOW2008

MECHANIC
41,814 POSTS

Which engine do you have?

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Saturday, September 22nd, 2012 AT 8:26 AM

WAYNEWEATHERMAN

MEMBER
5 POSTS

Also has new o2 sensors, It has a 2.0 16 valve Ztech motor

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Saturday, September 22nd, 2012 AT 8:36 AM

KHLOW2008

MECHANIC
41,814 POSTS

These are what can cause a P0171

HO2S and sensor connection.
Vacuum systems.
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.
Fuel system.
Exhaust system leaks or restriction.
Engine cooling system.

A scan tool would help for diagnostics.

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Saturday, September 22nd, 2012 AT 8:59 AM