I've not worked on C206 aircraft for many years and my memory's a little hazy! The first points I'd check would be the fuel filter in the nose gear bay and the Fuel Control Unit finger filter. I've forgotten if the flow divider (spider) valve has a screen but I know there can be shut-off diaphragm leakage problems, so it might be worth having it inspected for correct operation.
Sorry I can't be of more help at the moment.
Crossed post with EXDAC!