Tracing a vacuum leak...
 

First post here, so hi all.

It's an 87 240, auto trans. When I told my mom to replace the timing belt on the car(I was far away), she didn't. So the belt broke, and the car sat for quite a few months. I finally got back in the area, and I am fixing up the car now. So I took the head off, had the valves worked to ensure they were ok, and put it all back together.

It runs ok, but it will stall on occasion when you let off the throttle to brake, and sitting in neutral and idling, I can hear a miss. Also doesn't like to shift into 3rd/4th to easily, but I haven't changed the fluid in it yet.

Most of the vacuum lines are hard as a rock, so I've been replacing them. There is one however, that I don't know where it goes(as I haven't gotten under the car since last year). Comes off the intake manifold, and drops down the firewall, then out of sight. Larger line, about 1/2" or larger O.D. What is this line for?

I've also read references to a kickdown cable for the auto trans on here. Would that be the other line attached to the throttle body, or is the secondary line for the cruise control? (I've always driven manuals, so I've never had to do extensive work on an auto)

edit: And when I turn the car off, I can hear the HVAC system losing pressure, and everything going back to a non-vacuum state. I assume this is not normal for the car to do upon shutdown immediately.

RE: Tracing a vacuum leak...
 

Check either the engine speed sensor for the stalling or the Power stage.

Yes the other cable should be for the Kick down.
Make sure it moves freely.

The HVAC will do that to some extent.

RE: Tracing a vacuum leak...
 

replace the gas?