Hi, can some one tell me how to change a coolant temperature sensor on a toyota previa, 2.4l gasoline 1994 or were its it located in the engine. Thanks

You have to remove the pass front seat. The brackets for the seat, and the sill plate has to come up.
Lift the carpet. Under all that is an engine cover with seven 12mm bolts holding it down. Once removed, the sensor is located forward of the valve cover and has a green 2 wire connector.
While all that is out, I would replace the plug wires, cap and rotor, and the spark plugs.
They hide under a cover on top of the valve cover.

I rate this about a medium difficulty for a mechanicly inclined person.