Hey Ive noticed that when I start up my truck in the morning it idles at about 1500 rpms and then very slowly makes its way down to regular idle rpms. This only happens when I crank up the truck for the first time that day. All the other times throughout the day it revs then goes quickly down to regular idle rpms. Do you know why this is happening?

 

It's to help light the catalytic converters off as quickly as possible. It's normal.

 

good thanks a lot