BAd radiator cap, low coolant or (leaking), Bad thermostat, cooling fans not turning on.
In park or neutral, no.
the coil
Does your cooling fan work?
Its prob the radiator fan. Or you are out of coolant.
The radiator cooling fan is most likely not working.
You need to check the operation of the radiator fan.
Thermostat? or radiator? Greg
Engine idling in park.
If the coolant is low ( watch for leaks )it will act as you say. Fill it up , leave rad cap off for 5 minutes while idling to bleed air, and try it.
Defective cooling fan or bad fan relay.
Taking your foot off the accelerator.
Check coolant level Cooling fan working? Dirt or clogged radiator? Defective radiator cap?