hdmotorsports

This is a fun one. Truck runs at normal temp until I try to pass of highway at 80 to 100 mph. Then the temp skyrockets to 260, shut off the ignition and coast for about 3 minutes. Turn on the truck temp drops to normal and runs at 80 for hours with zero temp fluctuations. New thermostat, fluid. No issues at low speed or in traffic. Hose collapsing?