> 1981 Nissan Fairlady 280Z. When the engine
> is cold the car will idle up to about
> 2000rpm untill engine is at running
> temp.Then the revs will come down to about
> correct speed. What is causing this?
WHAT RAISES YOUR RPMS IN THE ENGINE IS COLD IS YOUR AIR REGULATOR VALVE AND COLD START VALVE. WHEN YOUR ENGINE IS COLD THE AIR REGULATOR VALVE IS ALREADY OPENED UP AND LETS ADDITIONAL AIR BY PASS YOUR THOTTLE CHAMBER, THIS IS WHY THE ENGINE RAISES RPM'S.