I have a 2000 Dodge Ram 1500 with about 130,000 miles.

When using airco the air suddenly stops blowing, although you can still hear the fan.
If you let off the gas a little, the airco comes back on.

When using cruise cotrol, it slowly loses speed.

Now when trying to drive with cold engine, the tranny revs around 20 and 30mph trying to change gears.
Getting up and going on highway..no problem.
After driving a bit, all tranny issues dissapear.

Engine light is on now. All fluids are OK and not discolored.

Does needs a tune up, though.

Whats the deal? What can cause a vacuum? Hose leak? Crack in distributor cap? Can it be something in the engine?

 

Definetly sounds like a vacumm leak. Big problem is they are very difficult to track down. Could be a simple as a broken vacumm tee, or as major as a cracked line, or even the vacumm canister for the vents. THis is one to take to a shop or the dealer for.

 

Are you sure those trucks had vacuum actuators on them and not electrical?

 

yep vacum,and usualy break at the fire wall where the dryer is,also under the battery traydue to battery acid leaking on
cruise lines

 

When you have a cold engine, start the truck and spray brake cleaner or carb and choke cleaner around all of the vacuum lines. If you have a cracked or broken vacuum line the spray will suck through the leak, and choke the motor for a second. This will give you a good idea where to look for a leak. Also you can usualy hear a leak pulling air or whistling.Keep us posted