Which temperature sensor? There is an air-fuel charge sensor, and a coolant temp sensor.
should be close to your thermastate. Follow upper hose from radiator to your engine. Should take you right to it.
In the M20 engine it's located on the thermostat houseing, on the M50 it's on the the front of the head intake side.
One scenario could be that the sending unit for the gauge on the engine is bad. Try to locate it and replace it if it is corroded and check the wiring to it also.
It is screewed into the drivers side head between the first 2 spark plugs.
On a 1991 Ford V8 engine, the temperature sending unit is typically located near the thermostat housing or on the engine block. For most models, it can be found on the driver's side, near the intake manifold, threaded into the cylinder head. Check your vehicle's service manual for the exact location, as it can vary slightly depending on the specific engine type and configuration.
It is on the back of the engine, just behind the distributor.
Mounted next to the oil filter.
Engine seal? Valve cover? Oil pressure sending unit?
yes it has both. at least in my 1991 ford ranger does
check the coolant temperature sending unit on a V8 it is in the front of the intake manifold
On a 1991 12-valve Cummins engine, the coolant temperature sensor is located on the engine block, near the thermostat housing. It is typically found on the driver's side of the engine, towards the rear, and is screwed into the block. This sensor monitors the engine's coolant temperature and sends the information to the engine control unit or gauge.
UNDER HOOD, CENTER, FRONT ENGINE AREA, FRONT DRIVER SIDE OF ENGINE, MOUNTED IN ENGINE BLOCK