Hard Shifting/Cruise Control Intermitten

I replaced some vacuum hoses and the PCV valve. Now the car sometimes disengages the cruise control or sometimes I can't get it to work at all. The cruise control/signal switch was replaced a year ago. The car also hard-shifts from gear to gear or when I put it in reverse. It happened less so after I changed the PCV valve. There's also a plastic pipe that goes from the air intake hose to the back of the engine that seems to be loose but I can't seem to be able to get at it and see it clearly to be sure. Any ideas?

What year Skylark?

If you have the 4T40E transmission from about 1998 or prior, there is a vacuum modulator on the front of the transmission which needs to be connected to constant intake vacuum. That controls the transmission line pressure, and without the vacuum supply the transmission will operate at full pressure, thus causing very harsh shifts.

The lack of vacuum there could also result in a lack of consistent vacuum at the cruise control servo, causing its erratic operation.

I'm sure it's some kind of vacuum leak. I can't seem to find a loose hose.

Sometimes the cruise will work at low speed for a mile or two, so I'm thinking it's a vacuum connection somewhere. I'd hate to have to take it in for that but I may have to.

In addition to the hose the vacuum reservoir and the check valve in line with that should be inspected. The reservoir is a black plastic sphere, about the size of a softball, and should be mounted in the left fender toward the bumper (hidden by the splash shield).

http://ww2.justanswer.com/uploads/Barlogio/2010-08-09_020018_79073406.gif

I know where it is. The connection looks OK.