1994 Mazda 626 ES 6 Cyl 2.5L
guage shows rapid changes in engine temp.
can't decide whether it is stuck thermostat, which would probably show a slower temp. change, or the temp sensor sending unit which might show the needle on the guage moving or jumping up or down as it does. At times the guage shows engine running hot, but then cools down after a while, and then the needle moves slowly! ???
check your coolant level,if low,waterpump loosing prime but catching water when turning or going up a overpass