First off, I'm new here.Hello. I did search the forums but my problem is kind of weird and couldn't find anything similar. Here goes:

About 6 months ago my a/c stopped working in car. Turns out bad compressor. Had it replaced. First guy who did it said there was a leak somewhere and he couldn't put any coolant/freon? in it. Second guy did it no problem. So about a month ago it ran out of coolant. When I ran out I just refilled it using a DIY can. Then the idle problems started. Idle RPM would drop below 500 and it would shake. Then it started to fluctuate between about 700 and 400 and when it was low it would feel like it was almost about cut off but it always spiked back up. Also with the new coolant in the car would make a screeching sound when i started it and after I stopped the car. Now my car stopped blowing cold again and now the idle and screeching sound is gone and I am not having any problems. I have no idea. I have been doing research non stop. Sorry for the long post I just want to get all the details out. Also, when I try to use the heat it only works after the car has been running for like 15 minutes and won't blow hot when I am stopped. I work and go to school 5 minutes away so that didn't help lol.

I am not very car savvy but willing to try anything if I can get a tutorial or instructions. I just replaced my gf's radiator the other day, successfully.

The idle problems seem to be a/c related so that is weird. Again, sorry for the long post just trying to get all the details out there. If you have any suggestions or experience with this I would appreciate any help. Thank you.

 

That screeching is the accessory belt. The compressor or compressor clutch is bad. That's why it's causing idle problems.