Can someone help me with a picture of your engine under the battery cover? I believe I forgot to plug a rubber hose back in but I can't locate the hose.

 

hissing, sucking air? bad idle?

 

Are you talking about this area? I don't own an RL, but I don't think there are any vacuum hoses under there. All the vacuum hoses I know of come off the intake manifold. The only ones I know of that aren't right in the engine area is the one that goes to the brake booster on the top right of the engine bay and a couple small ones that I think go to the motor mounts. But none of those are under the battery cover.

 

^the ones i'm thinking of are the vacuum controlled motor mount lines

 

That was my first thought. I'm trying to recall if any go near the battery. I think the front tracks along the drivers side of the engine. Not sure if it actually makes it as far as the battery though.

Also, OP, if you hear hissing like justn said, it could be a snake.

 

the front motor mount line does indeed snake down underneath the battery tray.

 

Ah, good to know.

 

 

This is the pipe that I am talking about.

 

look at the rear center of the intake manifold...you'll see three vacuum lines for the engine controlled motor mounts..trace the farthest right line down towards the battery...I bet it's disconnected...

I do remember now that the front motor mount line is a hard line underneath the battery, I believe my initial guess is still correct. cuz I had the toughest time pulling out the rubber hoses from the hard line at the battery.

 

I had no luck finding the hose.