[FresnoDiesel]

I am now to this forum.

I just noticed that my temp gauge is not moving past the first notch. Looked at coolant tank and it is low. When the truck starts to warm up it runs/idles rough and loses power.

Can a bad/stuck thermostat cause this?

 

[mhatlen]

Most likely stiction or low FICM voltage or dirty EGR.

 

[ZMANN]

if it warms up the tstat is doing it's job