2006 Jimny Dropping RPM Idling & Driving

I have had my 2006 Jimny for around 2 months now and recently it has started to momentarily lose power when idling and accelerating.

My car usually idles at 1000 RPM but will now periodically drop to 500 RPM ish and really struggle to get off the mark with your foot flat to the floor! It will also do this mid drive and also after changing gears.

This struggling issue lasts for about 5 - 10 seconds and then the RPM shoots back up to where I'd expect it to be in relation to how far down I have my foot on the accelerator.

In addition to this issue, I also have a loud squealing noise that will happen every once in a while when the engine is running (this happens when idle and driving). This has been happening since I have had the car.

When I purchased the car in December 2020 I was told that it had a full service.

Does anyone have any ideas what could be causing these issues please? I would like to try and fix the problem myself if possible.

Thanks all.

Derk

If it weren't for the shrieking belt I would say sensor issue but the belt shrieking suggests a rotating assembly is binding, does it have air conditioning or just pas alt and water? Either way check all the above are free either by listening to them spinning with a stethoscope or by hand with the belts off.