i was replacing my air filter with a new K&N filter and i noticed a tube comming into the air box from the exhaust manifold. It looks to me like my 2.9 liter is recycling exhaust. I was woundering if anybody has ever disconected it and pluged it up. If so what happeded?

it is called a heat stove it warms up the incoming air to a carburator. as for why? i have no idea. sorry. i think it might have something to do with allowing a more complete combustion cycle thus producing less emissions. but im not sure

What the heat exchanger does is aide in warm-up. It allows air that has been heated by the exhaust manifold to preheat the air traveling through the air box, wich aides in faster engine warm-up.