Dodge Repair: Car tries to stall..., dodge intrepid, month of sundays

Question
Pete,
Thanks for taking my question.  I have to for you.
First some background info on car.  1994 Dodge Intrepid 3.3 L V6 w/ 175,000 miles.  Car gets general maint (oil changed, tires rotated balance, and I do minor mechanic work myself when needed and it hasn't been that often)
1rst question:
I changed the belts out about 4 months ago when weather was warmer.  Over the last few weeks as the weather has gotten colder I have noticed that after I crank the car up-no trouble fires up every time-but if the car is not warmed up yet (ie the end of my drive) and I try to roll down any window it rolls down real slow like almost seems like they aren't getting enough power (it could be the power window motor on the driver side but the others normally work fine and do so when warm).  Also there have been times where the car will sputter from take-off but then catch right away.  Over the last two weeks before the car warms up the belt squeels on take-off not during driving.  This past weekend I tightened the altenator belt up.  Well, this morning the belt did not squeel but when I went to take off the car almost stalled out.  I stopped tried again with similar results.  The third time I tried and it sputtered and then caught.  After I drove about 40 miles to work I stopped in the parking lot and tried to get it to do again.  I could not make it stall or even sputter.  The fuel injectors haven't been cleaned in a month of Sundays.  I tend to think that is the problem I just find it odd that I tighten the belt this weekend and the first time I drive it after this happens.  Any advise you can give would be great.

2nd Question:
I had some front end work done on the car around 110,000 miles.  Don't really remember what all they had to do.  This car for years has had a slight vibration at high speeds.  Over the last year it started with a awful vibration at about 38-40 mph and at that speed only.  Just maintaining that speed not when braking or accelarating.  Would vibrate for about two seconds and then taper off.  Doesn't do it every time either.  While this has continued the vibration at not only high speeds (interstate travel) but also regular travel speeds has gotten worse.  Tires have been balanced and rotated and there have been different sets on the car.  No unusual wear either.  When I take this car into have the front end looked at what all should I tell them to look at or do you think there might be something I can try myself before I take it in.
Pete, thanks again for fielding my question and I hope you and yours have a Merry Christmas.  

Answer
hello on the spuiter i would get some good fuel engt cleaner from the parts store and it goes in the tank happen to me a few weeks agao .

how are the ball joints it also could be in the tranny i would get it checked and get back to me what they find for sure pete