Where can i find a vacuum light?

I can’t find what hose runs to the intake manifold most forward vacuum port on my 1999 Jeep Grand Cherokee?

• I have 100% stock 1999 Jeep Grand Cherokee with a 4.0 liter 6 cylinder engine. Recently I noticed that it would not shift until the RPMs were over 3000, and then the check engine light came on. I checked the engine and noticed a vacuum port that was hissing with nothing connected to it. I looked all around for a line that might run to it but couldn’t find one. When I placed my finger over the hole quickly my engine shut off, but if I did it slowly the RPMs would drop until I completely covered it up. Once completely covered it would seem idle at normal. Once I uncovered it the RPMs would jump up for a split second. This is the forward most connector on the intake manifold. My power brakes still work. My EVAP purge solenoid is running nonstop and don’t know if this has anything to do with my problem. I’m not sure if it was capped off or if the line that connected it to something else just fell off. I was wondering what that vacuum is supposed to be running to.

• Answer:

  check to see if your cruise control still works..the vacuum line does fall off and it makes your idle jump. look very close for the disconnect line......... good luck