Normal Idle?

I have a 91 unlabled DX CRX.

When i start it up it idles at 1.6k

After i let it warm and rev the engine it goes to 1.1k

I never really paid much attention to it until tonight, i looked at it and it was around .6k-.7k

That was after an hour and a half of driving. Is that normal? or do i have to fix another thing? could it also be because i got a new alternator?

thats like mine too. mine goes aroun 7-8k though after driving around.

When the engine is at normal operating temp (lower 1/3 of your temp guage is indicated), the engine should idle at 700-800rpm (750 is optimal).

When started cold it should idle at 1100-1200rpm