2002 Ford Escort P0171

LCKYSTR81

MEMBER
2002 FORD ESCORT
4 CYL
FWD
AUTOMATIC
78,000 MILES

I have a 2002 Ford ZX2 and the Service Engine Soon light came on with a code of P0171. I was told this could point to a vacuum leak, PCV valve or the oxygen sensor(s). Just wondering what the best point of action would be? I had the PCV valve replaced about 6 months ago so I'm not thinking that is part of the problem. The car has also stalled on me a few times when I have stop at a stop sign or light and then it starts right back up.

Thursday, February 11th, 2010 AT 2:18 PM

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Lean fuel condition:

Low fuel pressure due to a weak pump or leaky fuel pressure regulator. (Use a fuel pressure gauge to check fuel pressure at idle)

Dirty fuel injectors. (Try cleaning the injectors)

Vacuum leaks at the intake manifold, vacuum hose connections or throttle body. (Use a vacuum gauge to check for low intake vacuum)

Leaky EGR valve. (Check operation of EGR valve)

Leaky PCV Valve or hose. (Check valve and hose connections)

Dirty or defective Mass Airflow Sensor (MAF). (Try cleaning the MAF sensor wires or filament with aerosol electronics cleaner. Do NOT use anything else to clean the sensor, and do not touch the sensor wires)

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Thursday, February 11th, 2010 AT 2:46 PM