evap leak sounds like a tough one. Depending on where he's smoking it from, could be issues where he's scoping it.
A good idea would be to look up someone who has a subscription to online troubleshooting... I can't think of the name, but there are at least 2 resources that list uncommon problems encountered by technicians, and their final solutions. Basically you enter in your symptoms, and you can see if any technician has ever had that problem.
Ya, you can wait until your fuel pump quits.
Could be TPS, could be IAC, could be a few other things maybe... idk...
It would be good to use an actual scope, not just a scan tool scope...