I have a 98' Cadillac deville and it should constantly read around 197-201 when you are driving. It will definitely increase when you come to rest: example at a street light. something is definitely wrong and should be checked.
water pump or thermostat housing crack
Coupe DeVille
when overheating occurs at highway speeds the cause is usually. a radiator or coolant circulation problem, Check for a restricted or clogged radiator.
The coolant temp sensor is probably doing its job. You may have other issues such as being low on coolant or a thermostat going bad.
The number of miles per gallon that the 1997 Cadillac DeVille can achieve is dependant on a number of factors such as the condition the vehicle is in or the driving style of the driver. However, the Cadillac DeVille is believed to get between 17 and 23 miles per gallon.
One reason a 1998 Cadillac Deville would cut off while driving could be the fuel pump or the car is out of fuel. Another reason could be the spark plugs.
You have a hole in your brake line.
17 city 26 highway. Expect around 20-22 combined driving.
the coolant temperature sensor is faulty. It will need to be replaced
From all of my experience with cars if a car turns off while in motion it tends to be the alternator.
It means you dont need to be driving such a fancy vehicle, lol look in your manual, it helps. It is controled by the outside temperature, it is just telling you that there may be a chance of ice on the road or wherever ice first forms, bridges etc.
crank or camshaft sensor check for codes put your beauiful car on the neutral when you're braking you'll stop to stall