I noticed 2 unplugged vacuum lines on my 300 so I connected them together. After seeing a couple of other pics on the forums here, it looks like the first pic, single line that I am pointing to should actually be going back underneath the intake manifold somewhere.

Does anyone definitively know where these lines are supposed to go?
*the sticker on my hood only shows the 3 lines together, it does not show the 4th single line.




Here is where I connected the other end as it was missing, obviously wrong, but I don't know what this piece is and where the 2nd line goes.




Thanks for the help

 

The hose on the throttle body goes to the throttle opener right behind the tps.

 

I don't know the SC300 layout, but to add to what Blfatsharp said, that sure looks like you've got it routed to the Heater Control Valve.

 

Thanks for the answer! By any chance would you have time to take a few pics?
All the hoses around the tps are already plugged into something, so I must have a few flipped hoses somehow.

 

Well figured out the problem.

Pic of what it should be plugged into:



The way mine is, notice a huge missing piece?



My best guess is that the prior owner took it off during maintenance and didn't put it back either to it being bad or some other stupid reason.

Not sure what a "throttle opener" is but now I need to go to the dealer and pick one up. Curious what it does as my car has been missing it the entire time I've owned it. The last 3 days the car has been running great, so go figure.

 

No idea what "throttle opener" refers to, but that looks like an EGR valve in your first pic. The P.O. probably deleted it. That would explain why the car ran fine all this time... Check some schematics to see if that's where the EGR is located on your car. It's on the other side on the SC400, so I'm unsure.