I have a code 25 26 and i ran propane around the vacume lines and it appears to have a vacuum leak at this part.... what is it what is the adjustment screw for the lines go under the plenum so its hard to say where they go

 

A/C Idle-up.
http://personal.utulsa.edu/~nathan-b...24vacuumsw.pdf

You need it (otherwise the A/C will kill the engine at idle), so you should find which of the several lines is actually leaking and fix it.

I'd start by tracing the small lines back to the plenum, then disconnect (from the tee toward the VSV) and plug (a golf tee is the traditional tool) the other end. This will isolate the actuation vacuum circuit from the idle-up circuit (large hoses). It will make it easier to decide which one is the problem. The vacuum line to the 3-port filter (on the plenum) is labelled #2.

 

I had a leak from my 'that thing' as well, looked like the connection for the lower vacuum line had a portion worn away from some other line around the area. Bought a new unit from ebay for something around 20

 

Hah I was just looking at this the other day wondering what it was for. I'm always amazed at all the vacuum lines the 3.0 has...

 

what does the screw do?

 

Idle adjustment when compressor is engaged