75 280Z which when it starts idles low, about 550, once warmed up idle goes to about 1050. I've checked the vacuum and its OK, adjusting the idle when cold to 800 gives a warm idle of about 1250. TB has been cleaned up, thermotine switch changed. I'm a little stumped. Any help will be appreciated.

Check your auxiliary air regulator (AAR) for power and operation. It's described in the Engine Fuel section of the FSM. Search the terms on this site and you'll find some recent discussions.

Thanx once again Zed.