If I remember correctly:
He normally places a drain tub under the vehicle and operates the vaporizer pump using IDS. If fuel comes out, he's happy.
The trick is testing the vaporizer injector. To test he uses a mity-vac. Place vac the pipe over the injector nozzle. Any vacuum build up whatsoever, in any way, is a restriction. This requires a new vaporizer.

Just make sure the wiring to the exhaust temperature sensors is good. There is a known concern for wiring braking just by the multi-plugs.

Unfortunately, I can't find any reference for testing on ETIS, but it's not my brand, so I'm a little rusty searching for info, sorry.