Low idle after O2 sensor change.
10-30-2016, 12:03 PM
#1
Junior Member
Thread Starter
Low idle after O2 sensor change.
Need help again please!! Changed the upper O2 sensors with original Bosch and ever since idle has gone down from 800 to 750 with slight misfiring, checked for codes and nothing. Was wandering if there is anything that should be reset after changing O2 sensors, thanks in advance.
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MZE55 (10-30-2016)
10-30-2016, 05:25 PM
#4
Junior Member
You don't have to reset your ECU after swapping O2's. That makes no sense to have to reset your ECU when changing O2's.
I would check to make sure you didn't order downstream(secondary) O2's and not upstream(primary) O2's. Your symptoms are very odd for just changing O2's especially the misfire issue. Also make sure they are plugged into the correct side of the harness. Sounds silly but anything is possible.
I would check to make sure you didn't order downstream(secondary) O2's and not upstream(primary) O2's. Your symptoms are very odd for just changing O2's especially the misfire issue. Also make sure they are plugged into the correct side of the harness. Sounds silly but anything is possible.
10-31-2016, 02:07 PM
#5
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2008 E350 4Matic, 2011 E350 4matic
Might not be related. O2 sensor are typically the same for upstream and downstream, the only difference is typically the length/type of connector. Bad O2 sensors might have caused the car to run rich, now it's running leaner and it may have been masking some other problem. Misfires are typically plugs or coils.
