So i got this annoying screeching sound while im in drive and accelerating. I cant pin point because it only happens when im driving not just accelerating in place. If anyone could help me out that would be great.
Things that could help
-When it first started happening i turned on my ac while driving and it stopped immediately
-It happens only when reving the engine while driving but not when in park
-Also while rolling in neutral and accelerating
-Gets louder the higher i rev
-Most of the time it is screeching but some days it doesnt do it at all
-The ac pump squeaks when i turn the car on and the ac is on already
So im leaning towards the ac pump but i wanted to get some other points of view before buying parts.

 

Be sure to eliminate your belt as a cause. That's a lot cheaper than an AC compressor. Sounds like your compressor has a bad clutch or bearing, but it could possible be a bearing on another pulley.

I had a mystery screech before and finally figured out the location by removing the fan and shroud, then starting it up. You can do that for a couple of minutes without danger.

I got an AC compressor on ebay from ky_scrap for thirty bucks including shipping and it is working great three years later...

 

x2 on checking the condition of the belt also check the belt adjuster.
to see if the problem is internal to the compressor simply unplug it, once power is removed it simply becomes a big idler pulley.

 

Did you figure out what it was?

 

Also, it would be better if you let us know the type of Rover, year and model in the future.