I have been making some changes to my fuel map and when i back right off the throttle from flat out the lambda readings show the engine running way lean until throttle is re- applied.
My question is should the engine:
1. run lean naturally cos fuel is denied as part of deceleration or
2. run rich cos it should be air thats being denied when the butterflies close?
I think it should be the latter cos running lean ought to be avoided whenever poss?