Vacuum Leaks. Common Places?

89 Cherokee 154k Command-Trac 4wd

Anyone have any common places for vaccum leaks? I've gone over most hoses and there tight. The upper intake manifold bolts were all loose, and that helped slightly. But immedaitly after killing the motor, I loose all vacuum. I can literally breathe through any vacuum hose. How do you get to the lower intake bolts? I can get to 2 of them, but the rest are blocked by the front axle and the exhaust manifold itself. How common is it for the gaskets to leak?

The reason I ask is the car runs like shit in general. When cold, it will buck if I give it anything more than light throttle. As it warms up, I can give it more and more until it runs fine. When it bucks, it backfires like crazy. Hot it's fine, except everyonce in awhile it will bog a little off the line, then stall, or it'll take off. I'm hesitant to think this is a sensor problem just yet since there seems to be such a massive vacuum leak. I did check the vaccum ball, and it's fine.

I did clean up all the grounds I could see in the engine bay anyway, and that did help me idle from being so unstable.

ANY help at all is appreciated. One more question-Any common places vacuum leaks from on these cars?

One last thing

Where is the cargo light switch? I mean the light wway at the back. Bulbs good, but it doesn't light up with the headlight switch or the liftgate opening. I searched and nobody mentioned it..

Axle shift motor vacuum lines......and
Vacuum lines that run under the battery are prone to having acid dripped on them are a few right off the top of my noggin...
Maybe its not a vacuum line problem after all.How old are the map,o2,cps sensors?Is the tps adjusted properly?

If you are sure its vacuum related then I would get a vacuum pump like a mityvac and hook it up to each line(plug the other end if need be) and apply vacuum and watch the gauge if it drops immediately and drastically then that line is leaky

Two lines that lead into the dash directly underneath the coolant bottle were dryrotted. I used some vacuum connectors and the vacuum I can feel with my finger has gone wayy up. And my vents work now!

It seems to be a tad better, but unless you press the gas ever so slightly when cold it will miss and backfire. You can give it more and more gas as it warms up, until finally its gone completely.

02 is new. CPS, MAP, and TPS are unknown. Map has vacuum and the engine runs ever worse with the vacuum disconnected but plugged, so I assume that's adjusting something a little bit. CPS I have no idea how to test, but the fan comes on. Does this have a seperate switch for the fan, or is it controlled by the ECM based on CPS readouts? Because the fan works.

TPS? No idea how to check. I've disconnected every connection and cleaned all grounds I can see, including that one next to the bracket that holds the oil dipstick.

Do you test these by Ohming them or what?

I'll check the lines underneath the battery and let you know.

Oh, also, the lines to the shift motor were disconnected. 4-wd works now.

Also check the vacuum bottle behind the front bumper on passenger side those lines tend to crack where they enter the bottle. Bottle itself may also have leaks.

Also check your EGR function - if it is faulty it will buck and kick from stop with throttle...