Connection from Valve cover to intake

[Chris97K1500]

I've been looking my truck over, just making sure nothing looks out the ordinary. Well today I saw something that I am wondering what it is. It's a tube from the passenger side valve cover that connects to the air intake tube right before the TB. What is it? It seems as though it would be putting very hot air into the air stream. Doesn't make sense to put hot air right before the TB. Has anyone plugged the hole on the air intake tube and then put a filter on the tube from the valve cover? Just wondering, Chris

[WEFs99]

PCV hose? Usually they go to a vacuum source.

[Chris97K1500]

I don't think it's the PCV hose, I believe it's on the driver's side. By looking at the write up on how to replace the PCV from the board, I found that on my truck. Any other ideas? Chris