2003 Subaru Legacy Problem accelorating

2003 SUBARU LEGACY
130,000 MILES • 4 CYL • AWD • AUTOMATIC
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KTK1277
  • MEMBER
  • 1 POST
Hello,

My 2003 subaru legacy is hesitating a lot when I initially accelorate. It doesnt stop hesitating until i reach about 25mph. Sometimes it hesitates at higher speeds such as 50mph.
I changed the upstream o2 sensor after a mechanic told me that was the code it showed. Now it hesitates less frequently (maybe every 3 or 4 red lights), but still happens. Any thoughts on what it might be?

Any info would be great.
May 25, 2010 at 1:55 PM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.
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RASMATAZ
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 75,992 POSTS
Inspect and test the following


Oxygen sensor
Catalytic converter
Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Could also be an ignition system problem such as:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires
May 25, 2010 at 6:56 PM
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