So i used to have a Chevy Lumina with a 3.1? Anyways, it was Fuel injected and had coolant lines that ran to the throttle body, right around the butterfly. This canadian guy I was working with told me that was to prevent icing and frost in the winter time.

Is this true,
Does my 90 4runner 3.0 have that too,
and is there a way to route some hose to bypass this throttle heater?

In Aviation its called it Carb heat, but, its for carburetors not FI. Also airplane Carb heat is selectable and it draws unfiltered heated air from a shroud around the muffler directly into the carb to knock out that ice. Just for fun

 

Yep, right under the opening where the air hose fits, there is a coolant line running through the throttle.