1999 Chevy Silverado

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Inspect wiring to oxygen sensors. If OK, inspect oxygen sensors. To learn how to check an O2 sensor follow the link below.

https://www.2carpros.com/how_to/how_to_test_oxygen_sensor.htm


Let me know what happens with fuel pressure at rail after repairs are made to O2 sensors.



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Okay i changed the pump fixed the pressure drop but still has a trouble code random mis fire?Should i try and check the 02s?The wires are in good shape and not touching anything.But the 02 trouble shooting says you cant check with a miss fire.Pass cat seems much hotter than driver side?Any other things to look at wires are two yrs old same with the plugs.

I would suggest first checking out the 02 sensors before going any further. Especially on the side with the hotter catalytic. Is the cat. glowing red or orange? An oxygen sensor failure can lead to incorrect readings of exhaust gasses. The faulty sensor can cause a too-rich or too-lean condition. Too rich and the catalyst can melt down. Too lean and the converter is unable to convert the hydrocarbons into safe elements and may not pass a state inspection. If O2 sensor failed then it probably has damaged the converter as well.


Let me know how the sensors test out and I will follow up.


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