1999 Ford Taurus Engine Code

1999 FORD TAURUS
200,000 MILES • 6 CYL • FWD • AUTOMATIC
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MTTICE
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  • 1 POST
I have a 99 Taurus with almost 200,000 miles. The check engine light came on and the code was PO171. This gave me either a)oxygen sensor, b)Ingition misfire, or c)fuel injector problem. The car has also been almost but not quite stalling for about a month now. How do I narrow down what could be wrong?
Oct 29, 2008 at 8:24 AM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
Hi mttice and welcome to 2carpros

P0171/P0174

A lean fuel condition can be caused by:

* 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
Oct 29, 2008 at 8:31 AM
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