Jon,

That is the air intake preheater hose. It draws hot air off the exhaust manifold and directs it into the air filter box. When ambient temps are low a thermostat in the air box opens a door to this inlet and draws preheated air into the engine. Not having a functioning or cracked hose is no a big deal ... but the air box thermostat that opens and closes that door often malfunctions,leaving the door open to super hot air even in summer temps. That very hot air is suspected of frying the Air Mass Meters in many Bricks. (an AMM is a very expensive and vitally important part of the fuel injection system)Now that spring has arrived here in the Northern Hemisphere, it's a good idea to open that air filter box and make sure the door to the preheater is closed if temps are above 60 degrees F. Good time to change the filter as well. If the door is not closing replace the thermostat (15 bucks) or you may find yourself replacing the AMM (300 bucks)

Some Brickheads simply block off the intake to the preheater and leave the cold air door open all year round. That works as well if you don't live in an area where winter temps are extremely low. Even in those areas having it blocked off is not much of an issue. Hope this helpful to you.