Codes, p0171,p0174,p1153 CEL

2003 TOYOTA RAV4
224,000 MILES • 2.0L • 4 CYL • 2WD • AUTOMATIC
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BLUSKY310
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  • 1 POST
I am having this lean check engine light and cannot diagnose it. Replaced new O2 sensors, MAP sensor, throttle body gasket. STFT stays constant at sixteen to eighteen percent even when the engine is revved determining it is not a vacuum issue. What can it be?
Oct 29, 2017 at 8:13 PM
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KHLOW2008
  • ✓ASE Certified Mechanic
  • 41,814 POSTS
  • ASE Certified Mechanic
Have the fuel pressure and fuel flow tested.

A weak fuel pump or clogged fuel filter can cause this.

Check the ground circuits around the engine, poor ground connections can affect readings causing the ECM to read wrong and trigger the MIL.
Oct 30, 2017 at 8:04 PM
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