Daytona 955i Idling Fault

Welcome Alan.
It sounds like a classic case of leaky IACV hoses or throttle body gasket. There’s lots of info around the forum about it so have a search around.
Might I suggest you post a thread in the newbies section introducing yourself too.

 

I had this problem many moons ago and it was CO levels that needed adjusting. Needs a mechanic with a CO meter they can shove up the pipe really. Followed it up with a TB balance and has been sweet ever since (ie for many years!)

 

Air leaks from either of those sources will not cause it to die, it will cause high idle speed

I would agree to balance the throttles as first course of action