terrible gas mileage

2006 HYUNDAI SONATA
104,000 MILES • 6 CYL • FWD • AUTOMATIC
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MGALICKI
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  • 5 POSTS
what would cause a Hyundai Sonata to make gas mileage drop to 1/2? I keep oil clean, tire pres correct, new air filter, & plugs.
This is a big difference, any help?
Dec 28, 2010 at 3:00 PM
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RASMATAZ
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  • 75,992 POSTS
Could be running rich due to the following

1.Excessive fuel pressure can be cause by restricted fuel return line
2.Defective Oxygen Sensors.
3.Leaking injectors and fuel pressure regulator.
4.Coolant temperature sensor out of calibration.
5.Restricted air intake system.

Dec 28, 2010 at 3:33 PM