92 Lincoln Town Car Cartier is making super strange noises

lincoln
brakes
noises
transmissions

#1

My Town Car was dying on me. If I drove on the highway for a little bit (basically keeping a speed over 50 for more than 10-15 minutes) the Town Car would die on me when I slowed down, say for a stop light or at a drive thru. Didn’t happen every time, so it was pretty hard to show people. Eventually I was told to replace the idle air control valve, so I did. I was letting it idle after changing the valve, and if I played with the throttle, I could get it to die. But playing with it aside, I havent had it die on me. If I sit with her on for a few minutes, you can hear the idle drop, but it keeps going. Anyway, after changing the valve, what seems to be the intake manifold started making a loud whine, audible in the car when driving. The whine dies off when I give it some throttle, and doesn’t seem to be present at high speeds (maybe I just cant hear it). Another weird thing that happens is when you are slowing down the transmission doesn’t seem to be downshifting properly. The speedo will say about 10 and then the car will come to an abrupt stop, making the whole car lunge forward. This also only happens occasionally, and I can’t seem to tie it to doing any one particular thing, besides braking. Any ideas? Thanks for any help!