i have no clue why my engine temperature guage does not work at all. i replaced the coolant temp sensor and that sensor that plugs into the driver's side of the engine (no idea what it is). my service engine light isnt on but i am getting s hitty gas mileage, like ten miles to the gallon. i talked to a guy at the local murray's and he said if the temp guage is out, then the engine is spitting in random amounts of gas, leadingto poor mpg. is he right? someone please help me!!!!

 

What year and engine is your Blazer? We need vehicle info.

 

sorry, i have a 93 with a 4.3 vortec in it. the car is a 4x4 if it matters. thank you

 

Remove the plug off the sending unit in the passenger side head. Have the car turned to run and ground out the sending unit wire. The gauge inside should move and pin at full hot. If it does that, replace the sending unit. If the gauge still does read a normal operating temp, then change the thermostat. I would just go ahead and replace it anyways.