I know your post is old but did you fix a/c idle up? Likely the issue is that the rubber diaphragm inside the idle up actuator ("Diaphragm Sub-Assy, Cooler"), the thing with the plastic slotted screw on top, has become hard and cracked and no longer holds a vacuum. That rubber diaphragm is the key component inside that thing that opens a port inside the diaphragm housing and lets filtered air from in front of the throttle body bypass the throttle body and go directly into plenum to make idle go up. The screw controls how much air bypasses through the that port. The vacuum switching valve (VSV), which is usually mounted on top of valve cover, is just an electric solenoid that allows vacuum circuit to open sending vacuum to the bottom of actuator to pull the diaphragm down against a spring and open the port inside. Its easy to check that VSV is working, and easy to check if actuator diaphragm is intact. For the VSV, you can check operation with engine off first. Unplug electric connector to it and connect a 12 volt battery using small alligator clips to the terminals in the VSV. When you complete the circuit you should hear a click. You should be able to feel it too if you put finger on the VSV housing. The secondary check is to plug harness back into into, turn engine and a/c on, make sure a/c compressor is engaged. With a/c on your VSV should be getting voltage to open vacuum circuit. Pull the vacuum hose off of it that connects to bottom of idle up actuator. Put your finger on that VSV inlet tube that you just pulled vacuum hose off. You should feel some vacuum. If you do, then your VSV is fine. To check if the rubber diaphragm in the idle up actuator is intact, you have to apply a small amount of vacuum to the small "L" shaped vacuum port on the bottom of actuator. You can use something like a Mityvac with gauge on it. You should be able to apply a small amount of vacuum to it and the gauge should not move. You can probably test the vacuum also by mouth. Take the hoses of all ports except the bottom "L" shaped one. You can ether suck or blow on that remaining hose and you should not be able to really be able to move air either way, or at least not very much at all and then it will stop. If you can keep blowing or sucking then the diaphragm is shot. There is another thread on this A/C idle up issue. If the diaphragm is shot, you'll have to get a new part, if it has not been discontinued. There is a post on how to use another actuator from a Toyota van as an alternative if your part has been discontinued. It may not have all the same ports but the post shows how to reroute hoses to make it work. There is another way also to use a donor actuator just to get the diaphragm from it but its quite involved as you have to separate the diaphragm housing by grinding the edge or other means and then secure it back together. I had done it this latter way. Working on posting some pics in the other thread.

 

@twotwore Thank you for the great info! The idle-up actuator for these earlier trucks seems to be discontinued indeed, I can only find outrageously over priced used ones on ebay. Could you please share the link to the thread you were referring to? I would definitely be interested in an alternative, whether it be using an actuator from another model and rerouting vac lines or modifying/swapping diaphragms.

 

Here's the thread:
https://www.yotatech.com/forums/f116...70/index2.html

Let me know if you have any questions about how I did it.

 

@tlfromai yeah man I just saw your thread, thank you. no questions, you did a good write up and great pictures. i'm ordering those parts now and will go with the easy T method. I'll tag you when my build is done in a few weeks, now to be complete with COLD AC!!! thanks to you. *fist bump* haha

 

Check that thread again I posted pics.