Terran Vs. Protoss Help

Hello Fellow DayKnights!

So I have been coming up with a dilema. I can't figure out how to get mech to work verse Protoss. I can get it to work pretty well against Zergs because of the Thor'e anti air power and then the Siege Tank can rain havoc on any ground unit really. And verses Terran players, usually they go Bio and it is relatively easy. But I have yet to really get a Protoss player. Immortals with their shields just crush through my tank lines and then the air that I do have gets shut down by either stalkers or on the rare occasion tempests (as I am still in only Gold). So does anyone have any suggests as far as Mech Vs. Protoss? I am a little stumped.