Volkswagen Polo car cutting out

Hi Looking for some help

Recently bought a 1.0 Polo,
everything works fine on it however the other whilst driving along the car decided to cut out on me...it would not allow me to accelerate and the battery light and temp gauge were flashing.

I pulled over turned the car of, left it for a minute and turned back on...the car would turn on fine however straight away it would start juddering (basically losing power) until it would cut out.....i had a friend who had a look couldn't see anything wrong but just wouldn't stay, so he was fiddling around and took and disconnected a sensor by the coolant pot (i believe it is the coolant level sensor) we towed the car to his, by the time we got it back the car was working fine.

this has again happened twice to me since....with the final time the battery cutting a few times before all the juddering stuff, everytime to help sort it i have taken that sensor out for 15-20 minutes and it will work again after that.

Is the problem a fault with the sensors or not?

any help would be appreciated or any other explanations.

Thanks