Cars rpm's are high when started cold but lower down when it heats up

[gstrb91]

my 91 gst rpm's are high when i start it in the morning around 2100, if i start the a/c they drop to around 1500, once the car heats up the rpm's drop to normal range and lower with the a/c on, what do u think it could be?

 

[oldman]

Perfectly normal. The FIAV increase the rpm during cold start to warm up the car quicker.

 

[oldman]

FIAV = Fast Idle Air Valve http://www.vallotton.com/fiavblockoff.asp