I admit i bought a set of 4 aftermarket for 99-04 discovery O2s from ebay. The back seem to work fine or are they? I don't know anymore. Closed loop to open loop fault. I just orded O.E. front o2 sensors and if it fixes the problem.. why? lol but please feel free to analyze these readings and what could possibly be a logical explantion.. I'm confuse how this system works.


thanks for watching!

 

What's the fuel trim look like when you drive? How are the connectors for the sensors? Seems like they're grounding out.

Long term trim is maxed out as well, that's not a good thing. You're over fuelling. I'd check the plugs for signs of quenching and then check the coil output.

Are there any pending or current codes?

 

Get an elm327 bluetooth and an old Android phone off of ebay, download the free torque app and have it chart the 02 sensors.

Often o2 sensor issues are related to coolant in the exhaust. New ones will start out ok and get steadily slower to respond - oem or otherwise.

 

I don't understand chart the o2 sensors, i can chart the rear ones that have a signal but as soon as i start the vehicle the front ones don't work anymore or the computer doesn't read anymore.. maybe a ground but the ecu grounds it.. so i'm thinking its my ecu? very annoying to watch fuel and performance loss waiting for parts.. it's my only vehicle