It's probably the belt slipping. Check for belt tension. When an engine first starts the alternator works harder to recharge the battery. During that time, the alternator is harder to turn and if the belt isn't tight enough there can be some slipping between the belt and the pulley.
Sounds like a loose or worn belt, alternator or fan tends to do that when they get worn or loose.
It is very likely you have something wrong with your engine.
If this is a general noise, it could be the transaxle. When you are accelerating, the engine is pushing the gears, and when you let go of the pedal, the vehicle starts to shift back down. If this is an engine noise, it could be predetonation or a valve problem.
accelerating
If nobody pushed it, then it had to be either gravity or the wind.
have brakes check
Hey ya i have a 1994 grand am and i was having this same problem. What i did what replace the spark plugs. After i did this i took the car and and when i floor it no longer stutters when accelerating.
I have a 2004 freestar that also makes a squealing or "whistling" as I call it. I've had the ford mechanics look at it and they said the brakes are fine. I think it has something to do with the alloy wheels. The whistling starts on our van after it goes above 35 mph. As far as I can tell it's not a major problem just an annoyance.
You need to check the throttle positioning sensor.
I would replace them, There probably worn out. Once they get alot of miles on them they get a coating also that makes them squeal.
it hesitates because its governed and it wont let you go over 100 mph so when your accelerating it starts to hesitate around 70 to 80 mph you cant go over 100 mph
Most likely the serpentine belt, when you rev the engine does it get louder, once the car runs for a minute does it go away or it may still do it.....If this applies most definitely I would have the serp belt checked or changed...