S type eml

[sjshepherd742]

I have an unusual issue with my 2002 4.2 S type R. When the car is in sport mode everything is fine but when I deselect sport the EML lights up and sometimes the restricted performance warning. The code (I think) is P0171, lean burn bank 1. When I clear the code and select sport mode I don’t have any issues. I understand that the gearbox settings change and possibly the suspension but does it alter something in the engine management when sport is selected. Two garages have looked at this but haven’t resolved it.

[mike020150]

When Sport is selected, apart from the gearbox changing down more readily, it allows the engine to rev higher before changing gear. Whether it also enriches the mixture which would mask something like a small air leak on bank 1 is less certain. I would be tempted to get a garage to try a smoke test to look for a small induction air leak(s). If nothing is found, at least you will have ruled out one of the simpler causes of this type of issue before delving deeper into fuelling and electronic problems. Mike.

[sjshepherd742]

Thanks for the advice. I have had two garages look at this, both did smoke tests and found leaks which were addressed. They Road tested the cars (in sports mode obviously, why wouldn’t a mechanic take advantage of someone else’s vehicle ).
But as soon as I get the car back and deselect sport the EML lights up again. Maybe I should try again and get them to test it without selecting sport.