[04 Diesel]

Truck will be running normal and then the gauge will spike for a minute then drop back to normal. Also truck starts to idle high. Wondering if anyone has any ideas or things to check thx![/QUOT
The high idle thing happened to me one summer when I was sitting in traffic and the truck got hot.

 

[Smokeeatertk28]

u might want to have ur thermastat looked at. or water pump. or it might not be any thing at all. but its always good to take a look at em.