Quoted from EaglePin:Before you replace the coil, have you checked the coil stop to make sure that isn’t the problem? It’s been a somewhat frequent issue causing weak flippers.
I struggled with this for over a year in another title. Turned out to be that copper looking stopper at end of coil. If replacing it - your best best is a rebuild kit that will also include the rod that might now be mushroomed at the tip. You'll also see some metal dust in the cab.