I had my 95 ford f-150 motor rebuilt and now because of having to reroute some vacuum lines and cap 1 or 2 my vents keep opening and changing to a different position,whats happening ?.

EGR valve may be sticking open

In the early 80s they incorporated a shutoff solenoid in the event of overheating. What happens is when the engine reaches a critical level it then opens a vacuum solenoid forcing the engine to stall to prevent it causing extreme damage. I am not sure its location on your vehicle but when it happens again, try clamping off some vacuum lines on the solenoids to find out which one clamped will the car start. hope this takes care of things. ps...change your fuel filter, It may be restricting your fuel.

The vents are operated by vacuum. if you are short a vacuum line that would be the problem.

I think you are correct , the audio store must of knocked off a vacuum line or a plug at the heating controls, this being a 1998 and conversion it may have some vacuum operated components and some electrically operated actutor motors that control the doors for the heat and the selector. i would start off by looking at the controls to see if everything is connected good,i think you will find something they broke or left off. the radio was replaced then i would have them remove it and double check there work,let me see if i can find a diagram for you, okay heres how it goes, the blend door which controls the hot or cold air is electrically controled with an actuator motor, the selector control to send air to the defrost or vents or floor is controlled by vacuum, theres an 8 port vacuum switch on the heater control that operates the selection, the vacuum line is brkoen or they broke or left off the 8port plug that sends vacuum to operate the valves to control the flow of the air. theres a main vacuum line that runs from the intake manifold in the engine compartment and this line goes in on the pass/side into the passenger compartment and then up the dash to the controls , i would start at the controls and make sure theres vacuum to the control and the 8port plug is plugged in, also check the engine to make sure the main vacuum line is connected, you would hear a hissing noise if removed, also start the engine with heater fan off and listen closely for a hissing inside the dash area by controls, if you hear this then it would mean theres a vaucuum line loose or off, good luck hope this helps. heres a diagram of the vacuum lines for the heater control.

Should only be vacuum on 1 of the 2 hoses to the IWE, the other is a vent line that is just hanging in the engine compartment.

Did someone redo the vacuum lines and accidentally connect the vacuum system to the vent on the IWE ? If so, this would cause some problems with the 4WD system.

I do not have Vacuum routing diagrams but check your underhood labels for this routing. If not, then try internet articles. The Vacuum routing through thermal vacuum trees are probably the cause. As thermal heat changes the ports reroute vacuum for idle step-up.

It could be the IWE ( Integrated Wheel Ends ) solenoid causing this. Here is the PDF version of the TSB from Ford
http://my.voyager.net/~sscully/file_tsb06_08_15.pdf

If you can check the vacuum lines from the IWE solenoid to the IWE, to see if they are cracked. Few others have had cracked vacuum lines from the vacuum reservoir to the check valve
Here is a block diagram of the vacuum lines.


Until you have time to check everything, pull the vacuum lines ( not the vent line ) on both IWEs, and cap them. This will leave the IWE engaged, so the gears do not get ground off ( if it is not too late ).

check the coolant level & condition of antifreeze make sure it is not dirty/rusty/muddy if thats ok try a new thermostat & radiator cap if the antifreeze is muddy you may have to blow out the heater core

sounds like it might be a vacuum problem check all the vacuum hoses and spray some wd40 around the base of the carburetor while idling. if the engine revs up then you have a carburetor base gasket problem or a leaking vacuum hose

Older vehicles usually do not have an actual oil cap. They have a PCV Valve. It is usually round and will have a 1/2" hose recirculating vapors. If you turn this about 90-180 degrees it will come off. This is where the oil goes...