[steve99]

Its quite possible the lightened flywheel has caused idle instability problems.

Idle stability has been a problem on these cars and lightening the flywheel could certainly contribute to the problem

Their is a lot of stuff happening at idle and not all the tables are defined and their is likely a lot of compensations ect applied that are unknown.

It also possible that it may cause starting issues probably less likely but maybe like with idle the ecu detects the rpms rise quicker than normal due lightened flywheel and the standard ECU logic over compensates causing a stall or rough hunting idle.

Almost everything the ECU does is based on an engine Load calculation which takes in various sensor inputs including MAF (mass air flow) MAP Manifold pressure ect.

Their are many tables that control idle that and likely many undefined tables and ecu logic that is still unknown in that area.

You will need to get your tuner to investigate.