I am facing this weird issue in my 2006 Vitz. The temperature light (COOL) not the red one comes up at the start just as it comes on usually. But then it doesn't go out like even after 30+ mins of drive it stays and sometimes it stays there even longer. When it does go out the car vibrates if I am driving slow and sometimes even the engine shuts off. Sometimes it comes up multiple times during drive and the car takes a bit of jerk every time it goes out.
I got it checked, serviced the radiator. The issue however kept popping up for a week or so and then completely vanished for 2-3 weeks until today. The car started fine today and then in the middle of the drive the light came up and then went away after a few seconds and then it came back and didn't go away for the rest of the drive which was around 20KMs.
My car is done around 150k+ miles. I am at the end of my wits here, any guidance would be appreciated.