fox with idle issue

Idle has been acting weird, normally it sits at 800 rpms but lately it has been changing, sometimes at idle it will sit at 950 and then go up and down between 700 to 900 rpms. The tps sensor and iac valve have been replaced a few months ago due to an idle problem that went away after i changed these two parts. Any idea what else it could be keeping in mind the iac valve and tps sensor have been replaced?