Ok, I have a 94 z with stock air intake (except for K&N and 1LE elbow) and I want to know what the hose running to the plastic piece of the intake (to the right of the MAF housing) is for. I recently did the TB bypass and when I hooked everything back up, the car's idle was really rough and choppy. When I took this hose off, It was fine. While it was running, I put my hand up to this hose and there was suction. What Is This Hose for, and why does my car idle terribly when it's hooked up? Thanks in advance guys, !

 

If the tube is kind of large, it's for your AIR pump. If it's small with a blue elbow, that's the vacuum line for your optispark.

 

It's kinda big. It connects on the backside of the intake piece. and where is the vacuum line for the Optispark you mentioned? Thanks.

 

94's don't have a vented opti

 

i would like to know the same thing

 

I am pretty sure it is an AIR hose. It said so in my k&n CAI install instructions. Just some crap w/ emissions so they can stop our cars from getting the optimal hp they need

 

Definitly your AIR hose.

 

would it run better if i left it off?

 

Leave it on if the AIR system is fine. There isnt power to be gained or lost.

 

I agree with leavign it on, but his post said that his car had a rough idle until he took the hose off, then it was fine.

That seems kinda strange.

 

Ok, I just took it down the road a little bit ago, and this is what was concurred. When I first started it, I pulled the hose off and I could feel suction. I then put it on and it started to idle badly, like it wasn't getting enough air. I left it on and took it down the road and let it warm up. I got out and again took the hose off. This time, no suction. So my boy and I concur on the idea that it only does this while it's cold. Reason being??? But thanks for all of the replies. You guy's know your stuff and such!

 

If you pulled it off and felt suction on the hose side (not the intake tubing side), it is because the AIR pump is running when the engine is first started cold and that hose is the filtered air supply for the pump. It is drawing air from the intake tract and that is why the suction was there (and not there after engine warm up).