Post-cat O2 sensors

[landrovered]

The answer is...it depends.

It depends on which error code(s) is being thrown. If you have the "slow response" code then no, If you have "failure" codes then the DME will kick the fuel curves to a more moderate setting (like limp home but not as bad) and you will not get the performance or economy that you would with the codes cleared.

My 3.6 has a tweaked DME and the difference in the curves is easily noticed, in a stock set up it may be less obvious but it operates the same.

So the answer is, replace your secondary O2 sensors if they are failing and then you do not have to suffer the issue.

Simply clearing the codes will give you a change in performance until they come back on.