Dodge durango..11mpg..Bad o2 sensors?

  • Thread starter Thread starter J.B.1972
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J.B.1972

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I have a 99 durango 5.2L that get's only 11mpg,no matter how it's driven,I noticed today that when I went to pass somone,the engine bogged down to almost no power at all,then the check engine light blinked 3 times and stayed on.These are the codes the computer put out...PO300,PO303,PO304 MISFIRE ON #3 AND #4 CYLINDERS..Is it possible that these codes are from bad o2 sensors?How do I test them?How many does this car have? 11 mpg sucks.
 
Your two upstream and 2 downstream o2 sensors have codes of their own. P0300 is a general engine miss-fire and the 03 and 04 are specific cylinder miss-fires. Sure lazy upstream o2 sensors could cause a miss-fire but it would be more of a stumble. More than likely you have plug wires breaking down or plugs. Then I would check your fuel pressure and fuel delivery volume. Do not have the codes cleared until the repair is verified and repaired. Clearing the code will make it difficult for a technician to observe the cylinders missing in real time. Depends on how many miles you have on your vehicle but you could have faulty injectors also. The fact that the miss happened under load would lean...(get it) towards plugs and wires first with a fuel pressure check just before.
 
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