Any help would be good...
I have a 2001 GMC Jimmy 2 door, it has a manual transmission.
and since it has been getting cold here (up north), in the mornings the engine revs up to 3000 rpm when not in gear usually while driving. i note this problem when i am stopping at a red light...I changed the air filter and most likely have to change the fuel filter, but could it be anything else be the problem?

Clean and reinstall your IAC valve.

Clean with throttle body cleaner and a toothbrush. also clean the hole it is installed into.

check for a broken vacume line possible line to pcv valve or at least a major size vacume line.