20-30* drop at idle is normal. Under load less due to the amount of heat being generated. What was ambient temp when you read that? Maybe you could IR it when it's high temp to verify the sender. I would verify temps for ya but I have my headers coming off. I would bore scope the rad to see if it's plugged and maybe start with a water pump, or at least pull it to check the condition of it.
I took the fan and shroud out today and throughly cleaned the radiator mostly small particles of dirt I wouldn't say it was filthy but had some dirt in it, I did notice a slight discoloration in a good portion of the fins a very faint brown coloring spent about 45 min with water and air
I may have gotten water on belt can clean/replace belt and clean up pulleys I read soapy water on belt and degreaser on pully?
If not the water I did change thermostat so could also could have been drops of coolant that made it on belt unlikely bit possible
Well I took the old belt off and cleaned off all the pulleys none made noise on their own or were loose with play with the belt off, I hooked up the new belt that was a bit tighter than the one that was on it.
So I started it up and noise gone, however when I turn the AC on their is a different sounding churp when the compressor kicks on, but then goes away...but comes back on if the ac compressor kick off and on again.
so will see if this helps at all maybe the belt was slipping, the pully for the water pump and tensioner were pretty shiny when I had the belt off not sure if they are suppose to be very shiny though maybe that was a sign of slipping...
Well, I tried to run the truck without the tuner chip and same deal, this time I got out and shot the radiator with the IR Gun and the middle was about 90 degrees and I could put my hand over the front of it and it didnt even feel warm while the truck was almost at red line on temp.
So truck went back to dealer monday and they say its the radiator so a new one is getting installed.
Hopefully thats the end of the overheating, I sure learned alot in a quick amount of time about my truck, onto tuning if this is finally sorted out thanks for everyone who chimed in.