Thermostat stuck open or no stat at all. Faulty temp sensor or Gauge.
It could be the fuse, but mine is because the floater that measures for the gauge is stuck.
The fuel gauge in a 2001 Cherokee could be having different readings due to a bad fuel sensor. The sensor is mounted inside of the fuel tank.
NO!!! A 12 gauge shotgun takes only 12 gauge shells. A 20 gauge shell would fall into the barrel and get stuck about half way to the muzzle. You would be in for a nasty surprise when you put a 12 gauge shell behind it and pulled the trigger!!!
More often than not, a fuel gauge problem is usually a faulty fuel gauge sending unit in the fuel tank.
Either there is a short in the fuel sender wiring or the sender in the tank is bad.The actual gauge is rarely bad.Good luck.
Bad sending unit in tank.
Most common problem is that the blend door is stuck or broken.
check for broken wire from fuel sender unit in fuel tank to gauge. check fuel sender unit for proper operation. float may be stuck in the tank then check fuel gauge
All the girls would chase me about.
Blocked radiator, low on coolant, stuck thermostat, air in cooling system
I would replace the thermostat. This sounds like the thermostat is stuck open.