[KingLT1]

Originally Posted by PeteSS2018

Problem solved ....

The good old piece of hose to the hear and listening around all the vacuum lines...

Turns out the low vacuum bypass actuator diaphragm on the supercharger is torn, so was leaking vacuum at idle. Have temporarily plugged the vacuum line and long term fuel trims are back to 6 or 7% on idle.

Thanks KingLT1 and others for comments.