Where does the vaccume hoses go on a 7.4 chev.1984?

There aren't the same diameter, length, od molded bends.

You don't rotate vacuum hoses.

You do check them for holes or tears and lose connections.

Have the vents checked. See if there's a leak or something block the air passage.

You will need to replace the Vaccum Booster Hose which runs from the intake manifold to the brake booster. I just fixed mine with parts from Partsgeek.com for less than 1/2 the dealer price. In addition to the Vaceum boster hose you will also need the booster adaptor which locks the vaccum booster hose to the intake manifold.

most likely a bad throttle position switch or an vaccum leak. try spraying all hoses and the intake with carb clean if the rpms change that object needs to be repaired

Is this a 7.4L engine? If so there should be power there when the key is on engine off. The other wire is a ground that goes to the pcm to pulse the injector. If you are having trouble with missfires on No. 7 of a 7.4L you may have a preasure regulator vaccum diaphram leak. This vaccum connection is on the No. 7 intake rail. To check pull the hose off and check for fuel in the vaccum line if there is the diaphram is bad and you can pick this up at you local parts store. If there is no fuel you can check to see if the regulator holds vaccum with a hand held vac. pump.

missing hose? connect sensor to constant intake manifold vacuum. should be a vacuum diagram somewhere under the hood

It sounds like you have a hole in the fuel preasure regulator. It is located on the back of the intake plentium near no, 7 intake rail. Unplug the vaccum hose and apply vaccum with a vaccum pump it should hold. You may have a rich code stored also. If you pull the vaccum line off and fuel runs out this is your problem.

there is a little set screw on the tbi driver side , if its rpms are very high you have a vaccum leak ,

you both need to go to advance auto and buy the little book for your cars, it has vaccum diagrams, i used one when i changed the intake on my 83 camino

remove the vacuum line and either 2 nuts or 2 bolts holding it to intake manifold. clean gasket material from mating surfaces and reinstall.