Dear All,
How long will it take for the adaptive values to reset if you don't have a Nanocom or other device. Mine has been running rich due (I hope) to a poor ground from the MAF. Its now fixed, at the MAF I have a good battery voltage supply, a good earth and the MAF sensor is reporting 1.45v at idle rising to 2+ volts on throttle (no load). She is still running rich, and I've replaced one of the lambda sensors which is reflecting what the other is showing, it thinks its running lean (4.9 - 5 volts).
So is this a wait for the values to reset or another problem?

You'll need to wade through it a bit, but in this thread https://discoweb.org/index.php?threads/reset-adaptive-values.92885/page-13 there's some software that can be used with an ELM327 OBD dongle that alleges can reset the adaptive values. Admittedly I've not tried it but as I have a Nano I've no need.

You certain there is no missfire?

The lambdas detect oxygen in the exhaust gas stream. A missfire dumps unburnt mixture into the exhaust stream, which raises the O2 levels. The Lambdas see that oxygen, and report back to the ECU as "lean condition", which causes it to enrich the mixture. Ofcourse the dead cylinder doesnt respond so theres still too much oxygen and the ECU will just keep adding fuel until it reaches the adaption limit and then will register a fault code. Meanwhile the remaining cylinders are running way too rich.