I have a 1999 F150 extended cab with the 5.4 engine. The vacuum line coming from the back of the throttle body, which seems to be around a foot plus long, is starting to degrade. It seems quite thick, and I don't want to cut it off without the new one handy. Does anyone know exactly what size it is, and if it is an available parts store size or dealer only item? I also have been hearing a small vacuum hiss for three years now at a certain throttle position and for only that moment until I have passed that mark. Has anyone had this and what leak did they fix and where to find it?
thanks , edman

 

I am also wondering about the size.

This is one of my leaks: (replaced it with a piece of fuel line/hose)


I have been thinking of replacing the entire PCV system with all new lines since i still get the P0171 & P0172 error codes
In the summit catalogue they use "AN" for sizing on their hoses, anyone who knows how many "ANs" the PCV lines/hoses should be?