Low idle fluctuation

[Docflo79]

Hi, I have a 2005 eddie v8 4x4
Some days my idle is normal and once in a while (maybe at least once a week or more) my idle falls to 600,580,500 rpm range or it bobs from 640 to 580rpm(estimate) in gear only if i put it in park it goes back to normal.
It used to also idle a little high along with dropping on occasion. I found some vaccum leaks and fix it but I still have the low idle issue. I dont see a diffrence when i turn the wheel fully to the right or left. Not much increase with ac on stays around 600.
Could it be an emissions thing like charcoal can. Bad throttle body, i was thinking bad pcm(i had it reprogramed at dealer) didnt help
I have replaced so much on the truck for other reasons.
I replaced:
Intake manifold
Tps
Egr
Cleaned the injectors
Spark plugs about a year old
Purge valve
Fuel pump
Fuel pump driver
Cleaned throttle body changed gasket
Booster check valve
Knock sensors
Belt
Coolant
All o2 sensors
Vacuum conntrol valve
I dont have an iac sensor
New battery
Probably forgetting some things
Thanks in advance

 

[Number4]

You clean the throttlebody while it was off the vehicle? And where the butterfly valve is there is zero gunk buildup?

 

[Docflo79]

Yeah, twice

 

[Joe in NY]

600 RPM is fairly common. Does it shake bad?

Also, DO NOT use the gauge cluster for idle speed. Under 1,000 RPM it doesn't reflect the actual rpm for crap. Will show 750~800 rpm most of the time for me but OBDII reports 600~650 rpm actual idle.