Excellent info there ringram!. I'll have a play with this as I've been hunting for a low speed, low load surge for a while now. I've also "reduced" the commend cranking air in my car and found it starts better.

On a different note, I thought I'd offer a tip on idle fueling for those still running a MAF. It seems that on some E38 OS's, the ECM will drop into SD mode for idle fueling and no amount of MAF adjustment will help. I get the feeling that it's what is termed "closed loop idle" in some OS's, where the "closed loop" does not refer to O2 trims, but to the airflow bias between MAF and MAP. At certain idle settings, the MAP takes precedence even if the MAF is not in a failed state. I'm still working on this one though.

Simon.