Help ID this line ... P0172 related?
 

CEL came on this afternoon, and it's a P0172. I guess I was glad to see it since I have been noticing some hesitation at around 1500 rpm, occasional stuttering at idle, and rough starts the last two morning. So, after scanning some posts, I went looking for broken vacuum elbows and hoses. Nothing stood out as immediately obvious, but I did come across this deteriorating line.

Can someone ID this line so that I can replace it? This is on the passenger side near the firewall. Will hot water and dish soap be enough to clean the metal line? I should probably clean it to help watch for future crud.

That is the water pipe. It carries coolant and will not cause your code. It does look like the rubber part should be replaced soon though.

diameter?
 

any chance you know the diameter of the pipe? I don't have a spare car to use to bring it in.

Here is the line:
Turbo Coolant Return Hose

It is linned so I wouldn't use anything light weight for longer than a few days.