need some help with 4.0 sohc vacuum lines


Well-known member
Apr 6, 2022
so to start off. there are two different upper intake manifolds for the sohc.
if anyones intake looks like this one

i could really use some help in figuring out where the hoses for the circled fittings go to.
So the 2 front of vehicle circles (2 on the left) come around to the front of the manifold and connect to a tee into one line and run down to the driver side vehicle where it goes into the purge valve with Green connector.

Purge valve
Drivers side (top right circle) goes to brake booster.
Passenger rear fitting(bottom right red circle) goes off to a couple climate control accessories one being a heater valve and other to the rest of hvac system. It has a 3rd line that goes to drivers side rear fuel rail to what looks like a regulator in valley of engine. This is the important line. You can see the top of bolt of the regulator in the last picture.

This is a '99 exploder

Let me know if you need more pictures.
thank you so much you seriously helped me out more than you know
ive been having this weird stalling out issue whenever i am up in the rpm and quickly cut it out. i dont think i have that line going to the regulator.
im gonna double check
thank you!!!!!!!
Dont mind the chaffed wires but to me it looks like you're on the passenger side of the engine and on my passenger side of the engine and has a fuel line connected to the end of that rail going to the driver side. Is it possible you have the fuel rails swapped from side to side?


this is the drivers side rear. You can see the regular. Either way hope it runs good with that line connected on your engine
no i have different fuel rails from a 97 explorer. that was the only year sohc that ran a return style fuel system. i used that so i didnt need to get a aftermarket FPR