Thanks Chris. I have cancelled the code, I'll see how soon it reappears. Lambda sensor was replaced in June. Engine runs well, son has no complaints. Will advise any developments.
Yes it usually does run ok, as the fuel air mix is correct, or it thinks it is. The code relates to the amount of adjustment (trim) the ecu is applying, to do so.
And I wouldn't discount the lambda purely on that basis though. Live data is usually required.
The throttle setting (my right foot) sets the air intake level, the MAF sensor measures its mass and the ECU then determines how much fuel to inject. The first lambda sensor analyses the exhaust oxygen content, advises the ECU, which trims the injected fuel volume. That is the trim we are talking about, right? The second lambda sensor checks the result post cat, but the ECU does not respond to its oxygen readings, so they have little purpose. When the trim necessary by the ECU to correct the first lambda value exceeds a preset amount - 20% ish - the fuel trim message is made and EML comes on. So, as you say, could be MAF sensor, could be 1st lambda sensor, could be air leak. If it's anything like the 3.2 engine, could be a brief excursion beyond bounds that occurs occasionally and is of no consequence
Thanks Chris, I hope I have that right. I shall take no action at the moment, and see what develops.