Hot Air Intake (HAI): Keeps intake air temperature hot even when it's cold outside. I haven't fully figure this out yet, I know that it's a thermally controlled valve on my air cleaner housing.
This prevents carburetor icing and speeds cold weather warmup. I highly recommend keeping it. If it's plumbed correctly, the flapper opens when the engine is hot to let cool air get to the engine.
Colo Springs, CO
'78 FJ40, '89 FJ62, '98 4Runner