Hello Scotty (or the wonderful mods),

I try to get my car advice here as you all are respectable, helpful, and know your stuff.

So, I have a 2010 Toyota Matrix Base. I am getting a weird thing happening when coming to a stop or idling. The car will go from 1000-950 rpm (approx.) to about 500-650 RPM (approx.). The car sometimes at such a low idle will shake a little and show the oil light blink on and off rapidly, but then when the idle goes back up, it is fine. The car seems to have a rough idle at about 1000 rpm as well. Other than that, the car does drive well in town and on the highway (all except when coming to a stop or stopping). I should mention that this doesnt happen EVERY single time, but most of the time.

Troubleshooting steps I have done:

1. This seems to happen mostly when it is in drive. It does happen in park sometimes, but mostly in drive when coming to a stop.

2. I have replaced the sparks plugs, checked both battery and alternator (both passed from Oreilly and my own tool as well), and changed the oil.

3. Sometimes when my car starts up, I will hear a squealing, which goes away after pulling out. It only lasts about 30 seconds or so. 

4. Since the idling issue has occurred, I now notice that my A/C seems to blow cold air and then blow warm air. I did check the cooler fan and it seems to be on. Not sure if it is related, but figured I would add that in as well. (This just happened the last couple of days)

5. The issue seems to have started a few weeks ago. 

6. I am planning on replacing the belt and pulley (Gates DriveAlign Belt Pulley 37015P | O'Reilly Auto Parts (oreillyauto.com)

I am at a loss on what it could be. Has anyone seen this before? Will replacing the belt and pulley possibly help?

I have uploaded a couple of videos to give an accurate understanding on what is happening. Please let me know if you need anything else to diagnose what it could be, I can do more videos for you all. Thank you 🙂 I dont have a ton of money, so trying to DIY this if possible. Wish I knew a good mechanic that would diagnose it with one of those fancy scan tools haha

https://youtube.com/shorts/OmL0v6nowbQ?feature=share

https://youtube.com/shorts/XcSC-ZmRTNM?feature=share