1980 280zx Rapid Idling Problem

[Volkmeister]

So Ive been reading around and I cant seem to find my issue on here. I have a 1980 280zx and recently Ive been putting work into it so I can make it my daily driver while I work on my bug but I cant seem to pinpoint this problem. When I start the car up it runs and idles fine around 8-900rpm. But after a little bit of driving it will Idle at 2000 and rev out at 2300. It doesnt do it all the time though. When I'm at a stop light and its doing this I just hold the brakes and let off the clutch a little bit i can get it to drop but when I push the clutch down it climbs right back up. I heard something about a BCCD? I have no idea what that is. And I also heard sensors can cause this. If anyone had a similar problem and can lend advice it would be much appreciated.

Things Ive already replaced.

Ignition Module on distributor.

Throttle Position Sensor

vacuum lines (all of them)

inlet boots, air filter.

AFM.

Injectors and Harness.

cleaned throttle body.

[Wade Nelson]

Did you get this fixed? What was the cause?

I was going to suggest looking at the Auxiliary Air Valve, but sawyour post was 5 months old.

[Volkmeister]

Now that I'm older and wiser I can put this one to bed. It was the BCCD. I ended up swapping it out with a functioning one from the junkyard just so things were copasetic. I recently had the same issue with my 76' Z and just eliminated the BCCD / EGR setup all together. Idle's way better and runs like a champ.

[rcb280z]

That's good you found it was "BCDD" Boost Controlled Deceleration Device. 

[Volkmeister]

Ha havent been on for awhile, I suppose not wise enough to use the proper acronym  ?

@rcb280z I replied on another post regarding this issue just now, but the short of it is I'm going to rebuild the BCDD and produce the necessary parts to do so. I'll post an updated thread if all works out.