The obvious answer is to swap back to the old hardware. There is a faulty part somewhere. Can't keep running that truck as it heats up in AZ. Here in about a month its going to overheat all the time, and towing or pulling a hill is going to be impossible without engine damage.

 

It started before the e-fans. E-fans were an attempt to fix the issue.

 

smokeshow is dead on. You're going to damage the engine if you don't get this issue resolved.

 

Aftermarket radiator or OEM? I'd check the fitting on the top passenger side of the radiator that connects to the overflow tank to see if it's partially blocked.

 

Easy test.

When engine is overheating (and running), grab the upper radiator hose and try to squeeze it. Now, while screaming in pain from the heat, see if you can cool your hand off with the lower radiator hose. If the upper hose squishes and burns you, you have a bad water pump. If the upper hose is solid and burns you and the lower hose is cool, you have a plugged radiator. If the top and the bottom hoses are hot, then you have an airflow problem. If the coolant isn't boiling out by this point, you have a bad temp sensor.

And if your engine isn't already switching back and forth on 2 sets of 4 cylinders, you just have a gauge cluster problem or someone tuned out REP mode.

 

Can a partially plugged heater core restrict enough flow to cause a hotter condition for the motor ?

 

nope.
we have plugged the lines off the WP and never had a problem.

 

You need to swap back to the old hardware. It is too hot here now to keep pushing your luck with that overheating.

 

I can drive around town and freeway with no problems. Never above 200. Only when i tow does it get hot which i have not done since engine hit 250. Just found out yesterday that my static fuel pressure is 45 so that should be where the lack of power comes from.

 

yea.. you should be at 52ish..
and 60ish WOT.