Cummins n14 idling too high

Hi Guys,
I have a 1994 International with a n14 cummins Celect.
my problem with it is, when it starts in the morning it idles on at 700rpm but when it warms up the idles goes to 900rpm
Can anyone say what may be causing this?

Thanks in advance

P.S i have no problem starting, i have no missing with the acceleration. it just idles really high when its warmed up.

 

Thanks for your reply guys

 

The Air filter its due changing just about now; however, the idle was like that even when the air filter was new. i use fleetguard fuel filter, never done any rack work since i have had it (2years)

 

There is no mud under the pedal, it moves freely all the way up and down. Intend to get insite hooked up but they are changing an arm and a leg to do it here (Jamaica) so i am just trying to see if there is anything that could maybe solve the problem without going that route

 

The cruise control switches will increase the idle when its cold and idling normal but when its warmed up and running high, the cruise control can not bring it down