Legend! It does indeed drop to P1 on decel. I had deleted the data in the first 3 load lines as it was corrupted by the usual street tuning conditions. Sorry for throwing you off course. It idles in P2, P3. That log and the tune was the 'custom' tune by a reputable workshop. I have since tuned the cruise points so it sits on 14.7. Having said that it's happy to cruise and idle leaner. I have to deal with pegged MAP sensors in the late model fords as we can't re-scale the sensor calibration in aftermarket software. It's far from ideal and will avoid it here if I can! The maf voltages vs airflow seems similar to the maf transfer function in the US fords so shouldn't be hard to work out. Thanks heaps Rossco I'll no doubt need some more help soon!