Vacuum leak?

[AKPirate]

Hi friends! I am happy to report that I have nearly finished my RV to flatbed conversion. I am having one last annoying problem with the engine; it seems to have a vacuum leak that I can't track down. The engine will fire right up and idle just fine until it warms up, then it does not want to idle. It runs and drives fine, but as soon as I take my foot off the gas, the dies. This is not ideal for any kind of city driving. Any ideas on where to start? I have some more info that I will share in order to help identify the problem but I thought I would just get this out there ASAP to start the process. Thanks in advance. 

[WME]

A spray can of carb cleaner. When the engine is warm and reluctant to idle. Spray all the gaskets in the intake system, the idle will change when the engine sucks in a shot of cleaner. Then if you can't find anything spray all the hoses hooked to the intake manifold.

[extech]

have you tried adjusting the idle mix after it's warmed up? i would give it a couple turns out to start with. then look for vacuum leaks with it running

[AKPirate]

2 hours ago, WME said:

A spray can of carb cleaner. When the engine is warm and reluctant to idle. Spray all the gaskets in the intake system, the idle will change when the engine sucks in a shot of cleaner. Then if you can't find anything spray all the hoses hooked to the intake manifold.

I was doing that today and found nothing, I did however pull one hose and put it back and the idle improved. I'm wondering if it may be one of the 2 relays. The Toyota part # 85931-35010 Relay, Emission one to be exact.... as it turns out it has been discontinued. What does one do when a part has been discontinued? 

[extech]

so is it an re or carb

[AKPirate]

16 minutes ago, extech said:

so is it an re or carb

Carb

[linda s]

The part you listed is a fuel heater. Only for diesels

Linda S

[AKPirate]

3 minutes ago, linda s said:

The part you listed is a fuel heater. Only for diesels

Linda S

WHY IS IT IN MY TRUCK!?!?! HAHAHA Seriously though, I think I have found a suitable replacement. looks like, Part Number: 909870200483 is compatible with this situation? Just now digging into possible solutions. I will post some video of the surge the engine is experiencing, as well as photos of the fuse box.  

[AKPirate]

Here are some shots of the fuse box, the relay, and a video of the engine surging.
 

Some history;

 

before it was parked and used as storage, it functioned perfectly. The last time I had to move it, I accidentally crossed the battery wires. After that it would not turn over. I ended up rigging an electric fuel pump to it just to get it home, worked, but had the exact same issue, when I stopped pushing the fuel peddle it would die. I’m guessing when I crossed the wires I fried SOMETHING? I’m starting at the relays, but there are a few other switches with power running to them.
 

Right now, I have replaced the mechanical fuel pump and as far as I know, there was never an electric pump? 
 

detail- while searching for a vacuum leak, I pulled a small hose leading into one of the switches and the idle instantly improved, it ran well until I pushed the gas peddle and then it died. It would not idle again until it was cool. 

 

hope these details, I will keep you all posted with any progress.