I like to Manipulate Data from my scan tools in MS Excel to help diagnose vehicles.
I'm certain there are a ton of different approaches and ideas, so please post what you got, some of your favorites.
A favorite of mine for driveability issues is Total Fuel Trim (Long + Short) against the Volumetric Efficiency (ie: Airflow) of a motor across the entire RPM range. So let's see what you Artists are really up to!!!!