Got lucky and found a Toyota EFI Tester SST, and yes it has been already spoken for.
The way the EFI checker is used is in the EFI section of the white and blue 5mge and 6mge Toyota Engine manuals.I have one of these. Do you know which adapter number or color is for the supras? I don't have the case or the manual. I was going to sell it once I had the correct harness adapter.