O2 ?

[GUMP]

Originally Posted by Jeff Stout

If a O2 sensor is going bad what will it do? Mine is showing 18 to 21 AFR now and car is fine and runs the same. Last month it was showing 16 to 18 AFR. No header gasket leak that I can hear or see. Plugs read normal and ET is where it should be. The sensor is about 3 years old with C12 and C16 for fuel

Where is the O2 located in the header? I normally change my O2 about once a year or at the first sign of an issue.

[FED 387]

Eventually leaded gasoline will wreck an O2 sensor---It also depends on if its a carb or EFI system---EVENTUALLY if you are using LEADED fuel it is going to fail ---how soon depends on the tune up if you are close initially it might last longer --OR -it might fail in just a few dyno pulls or it might last a few hours (50-75)--I don't think there is anyway to clean them either--you can try soaking the sensors(completely covered) in gasoline for about 8-12 hours to loosen up any residue and then GENTLY use a soft brush to clean any residue that the gas left on the sensor , then use soft cotton cloth to wipe the tip---might work might not -I could be wrong on all this tho--FED 387

[Jeff Stout]

Originally Posted by GUMP

Where is the O2 located in the header? I normally change my O2 about once a year or at the first sign of an issue.

Right at the collector, far from the head. Im going to look close at where the 4 tubes slide in collector now that Im thinking about it. One of the tubes is just the right length and only slides in collector a 1/4 inch. Thinking maybe that tube may have slid out just enough.