What is this??

 

That connects to the back of the stock intake "hat" (what bolts to the throttle body). It is the fresh air feed (vent line) into the passenger side valve cover to make up air that is pulled into the lower intake from the PCV valve.

 

OK but i realize it was off because i forgot to put ot back on last week it shouldnt have done any damage right??

 

I would be surprised if it ran properly with that off. That would be quite a bit of unfiltered, unmetered air entering the engine. By unmetered, it would not be seen by the MAF sensor.

 

i dont think it was acting wierd but my dad was the only one to drive it but he was only driving in town so it wasnt sucking up the much dust, so any harm done???? its still acting fine

 

Should be fine as long as he didn't park it inside of a machine shop with the hood open.

I ran my Bonneville a whole year with no air filter once, didn't bother it at all.

 

cool just wanted to make sure thank you all

 

Not too sure I would be bragging about something so careless... And just because you did not see any ill effects does not mean that there were no ill effects.

I would agree that the OP did no detrimental damage to the engine by leaving this vent tube off.