I'm still fighting my BCDD valve problem with the notorious high idle when downshifting. I've read a vew threads about going to a larger throttle body and eliminating the BCDD altogether. Has anyone done this and does it work or what else can I do to solve my idling problem on my '77 280. Any help is appreciated.

Was your car originally a California car? If so, the problem you describe could be caused by a bad altitude switch.

I know when I put the 60 MM throttle body on my 280Zx , I pulled the BCDD off the old TB and wondered what the hell to do with it. I finally just left it under the hood still hooked up but unattached to the TB. I forgot it was still there till I saw this thread. its been there about 12 years now!

I think you can just disconnect it without a problem.