Kyleblaqk

Hello! So I've just picked up a 1998 R50 with the 3.3 litre engine and automatic gearbox. Once the car is warm it idles a little rough, it's fairly stable in P but in any of the drive gears the revs drop and fluctuate between 450 and 600. When flicking between D and R when adjusting to park, for example, the revs are so low it cuts out. And when it's cut out, it cranks for a while before it wants to start again! I made a little video (link below) of it idling and switching between P and D, where you can witness the revs drop. I also pan to a multimeter just so you have more metrics to reference. https://youtu.be/ZjUrRVaSO3U?si=VibdLH7aSFLK_wNC On the road it feels smooth, it's only when it's stopped at lights for example where I feel like it's verging on cutting out at any moment. I'm also scared to come across any form of incline, as I very much doubt the idle is strong enough to hold itself on a hill of any sort I've cleaned the throttle body as per some forums suggestions and it wasn't so dirty anyway. One thing to note is that it does have an LPG system fitted. Though I'm told it won't even kick in until it exceeds 1300rpm or there abouts. And I have the system turned off as there's no gas in there anyway. Perhaps putting gas in might help? Seems unlikely, but I might do it just to be safe. If anyone has any suggestions for diagnosis then that would be super! Thank you all in advance