basicly its a hose that runs up the left side of intake manifold behind where u put the oil in on the 5sfe. it had nothing to connect to when i looked at it. then i found that on my fuel rail there is a actuater looking thing. i think its the stock frp and well that was unplugged also. so i put one and one together and i dont notice anything different? am i crazy.

it's a mystery hose

I believe that if that hose is disconnected you will always run max pressure on the rail, so it won't make a performance difference but I guess will wear down the fuel pump faster.

sounds like something that would create a vac leak if left disconnected. only way to know is to track the hose down and see where on the motor it leads.

Ya it would make a vac leak, I think if you actually get behind there is plugs into the vsv that is hooked to the rear side of the intake, but hey its toyota they run no matter what

Doesn't that look like the fuel breather line with that box being the regulator(is that what they call it) I remember that somehting like that off of my fuel line when I painted my car. Mine vented into the atmosphere.