Faster idle after a drive
 

I recently installed a Auxillary air regulator on my 3.3 turbo. It didn't have one when I bought it. When I start it up cold the idle goes up to about 1700 rpm until warm then goes down to 800. Then when I get to where I'm going, the next time I start it the idle goes up to over 2000 rpm and seems to slowly climb until I start driving again.

Any ideas what may be causing this?

Thanks!