Idle and fuel consumption issues

Should there not be a change in idle when I unplug the IAC valve? I have been suspecting this part for a while because my idle is above normal even after I have made adjustments and have cleaned all the parts. The other two things that I can think of that may be a problem is the TPS and the ECT. Sometimes the idle fluctuates and sometimes it does not. Also, when the engine starts up cold it idles as if it is warm already and then when it warms up it idles as if when it is cold. I also noticed that when I tap on the IAC valve the RPM's climbed a little. The TPS is brand new and learned, but that ECT hasn't been changed since I have had the car and there have never been any codes thrown for it. Also, sometimes when I have driven a car for a while or coming back from a long ride bear would be this howling noise coming from the throttle body area. It does not have any vacuum leaks as I know of common unless somehow I missing it. But I have checked all hoses and all connections even with the spray cleaner technique and idle stays the same. I am just needing advice on where to start and what to check and what do you think the problem maybe?