Hey! I've found these forums to be super helpful in the past, so I thought I'd make a post.
I've got an '86 720 (blue exterior and interior) but recently it has been a little funky. Usually, it warms up at around 2k rpms, then drops to around 700-800 for it's normal idle. The past couple days, it just won't drop from the 2k rmps. I've driven it around the past couple days and other than that it's been fine.
For a bit of background, it's got about 241,000 miles on it and I (and the previous owner) use it as a daily driver. I just replaced the head gasket a few weeks ago as well as thermostat, thermostat gasket, exhaust manifold gaskets, and intake gasket. I did the oil pan gasket a while back and it has a new clutch too. It's been running super smooth up until this point, and still runs and drives.
Thank you so much!