Dielawn

Amongst the multitude of things wrong with this Jeep I bought...the most prominent one has become this vacuum leak.

Okay, it's a 99 Grand Cherokee Laredo with a 4.7 Automatic QuadraTracII with 160k. The fan has blown through defroster only since I bought it. The cruise control does not work and now today it's idling rough, taking off rough but at regular driving speed it's fine.

Now I've check the common spots, (under the battery tray, side of the airbox, little black box behind passenger headlight). Sprayed carb cleaner everywhere I can access from the top. Any other suggestions? I can't find a diagram for the vacuum lines anywhere.

I *think* I MIGHT hear it by the belt on passenger side but I also think it's just a sound the belt is making. I don't have access to many "fancy" tools right now so I can't check the pressure in the vacuum line but I took the hose going into the side of my airbox off and it will only barely suck my thumb.

Any help appreciated! Thanks in advance!!!

Also, I heard about the check valve problem...I seen a post that said the one at the "help" section at Autozone would work, however I can't find where to install it.

ol"blue

Our '04 WJ has a 4.7 in it, and we've had it since new. Recently on a trip, on a long climb up grade on the interstate, the ac started to blow in Defrost mode. Never before had this happened. At the top of the grade, it returned to normal. Well I figured it was vacuum related, so I checked it out at home.
I removed the air filter & air box in front of throttle body. I found a 3" long 5/16" hose coming from behind the upper drivers side of the throttle body on drivers side, that connected to a plastic vacuum line. But the hose had a split in it where it attached to the throttle body. I removed it, and wrapped tape around it several times as a test, then reconnected it. Then I re-attached everything, and took a test drive. It cured the issue, and held almost until I could get the correct part.
Anyway, here's diagrams of the WJ vacuum storage canister, and the last one shows the line #4 at the throttle body and where it leads to along the passenger side.