Fantastic - solving two problems in one hit!
My 86 930 drives like jay71's car, i.e. lift off throttle and my head hits the screen. I had been wondering where to start looking. Sounds like decel valve not working. Like Rarly, I adjust my driving style to compensate but it can still catch you out.
My 85 930 does just the opposite. When I lift off throttle, it takes several seconds for the revs to drop to idle. Fast gear changes are a real pain do do smoothly because the revs don't drop fast enough.
I am at work at the moment so I can't stick my head under the lid to see what this valve looks like so I used our host's site to find out more about it. I couldn't find a listing for decel valves on '85 and '86 930s but I assume that my cars have one and its same as listed on 79-83 models.
Can someone please confirm that the decel valve is the likely cause of both problems?