temp issues

[tcollins]

i have a 2005 trailblazer i replaced the temp sensor after that i start the truck and the temp goes hot for a min then cold for about 10 min then normal all while saying temp hot idle engine but the truck isnt over heating i been driving it that way and now while i drive the temp guage goes hot then cold then normal alot but there isnt any actual over heating can someone who had this issue please help

 

[zora]

Sounds like a defective or wrong sensor or a connection problem. Why did you change it? Did you install a brand name sensor?

 

[tcollins]

yes brand new oem sensor and im now starting toi think maybe the thermastat as it stayed at cold this morning till i stoped to get gas then it went to normal then about 5 min later it went to cold and stayed there

 

[zora]

Change it before it sticks closed.