1999 GP GTP Window Problem

Hello. I recently purchased a 1999 GP GTP (coupe) loaded with every option available. Happy with the performance and all. The only thing bothered me while buying it was thhe high mileage...about 112000 miles. However, the previous owner took very good care of it (not a scratch on it).
Since I purchased the vihicle I have been noticing some minor problems. The first is that both the driver and passenger side windows open and close very slow most of the time, but sometimes they work just fine. Also I recently took the car through a car wash and ever since the insides of the passenger side window is getting scratch marks on it (vertical), and doesn't work sometimes. I have to give it a little push while pressing the button for it to start moving. Not sure whether this is related to the car wash or not. I know GPs are known for their window problems but my previous 97 GP GT never had any even though it had more miles than this one. Also, I have the premium sound system installed and the display sometimes goes haywire for about a minute or two the first time I start the car each morning. Thirdly, I was wondering whether flushing the coolant and transmission fluid would be a sensible thing to do. I have read that there are some issues about flushing the transmission fluid at high mileage. Is this true?
I would greatly appreciate some help with these issues. Thanks.

well i can tell you the display on the sterio is very common with these models, my radio display stopped working completely, had to sodder in a new bulb becasue thats what it was, and most likely thats what it is on yours too, ever since i replaced the bulb its been fine, theres a procedure somewhere on here on replacing the bulb. hope i was some help.

Thanks for your help. However, I am not sure it is the bulb. The display only acts funny for the first couple of minutes (or so) when I start the car for the first time in the morning. After that it works just fine. What I precisely mean about going haywire is that it displays all sorts of funny characters and my radio display. Also, I have noticed that as soon as I open my window it stops doing it...may be a coincidence.

I've seen posts before about the radio display doing what you describe, but I can't find it to post. If has to do with a capacitor inside the radio. Flushing the coolant if it looks dirty is a good idea. ID give it a thourough cleansing, and replace the Dex-cool with Prestone extended life, as it isn't a prone to sludging up. Under no circumstance, do you want to flush your trans fluid, unless you want a new transmission. Drop the pan and change the filter and only replace the fluid that was in the pan. As far as the window is concerned, it sounds like the window guide has come loose or the felt has come off, causing excessive drag and the window scratches.

I've seen posts before about the radio display doing what you describe, but I can't find it to post. If has to do with a capacitor inside the radio. Flushing the coolant if it looks dirty is a good idea. ID give it a thourough cleansing, and replace the Dex-cool with Prestone extended life, as it isn't a prone to sludging up. Under no circumstance, do you want to flush your trans fluid, unless you want a new transmission. Drop the pan and change the filter and only replace the fluid that was in the pan. As far as the window is concerned, it sounds like the window guide has come loose or the felt has come off, causing excessive drag and the window scratches.
Thanks richtazz for that. I did check the window guide and wola...you were right on the mark. It was twisted in the middle facing downward. All I had to do was to take a pen and fix it. As far as changing my coolant to Prestone is concerned, doesn't GM recommend DexCool?? What color should dirty coolant be?? Thank for all your help guys.

When Dex-cool gets dirty, it turns a reddish-brown color (it's pinkish-orange when new). GM suggests a no/low silicate antifreeze (which Dex-cool is) to protect aluminum system components. The problem is that without silicates, there is nothing to clean the sludge from the engine, and when you combine that with the long (5yr/150k mile) recommended fluid change interval, the sludge builds up and collects on cooling system components and mucks things up. I switch to the Prestone in the yellow bottle, it has just enough silicates to keep the cooling system sludge free, and when it starts getting dark (around 50-60k) I change it.