Honda Repair: honda civic, temperature sending unit, coil pack

Question
hi there i have a honda civic 1.4 when i start the car and leave it runing it reaches its correct running temp but when i drive the car it drops and when i go heavy on the gas pedal it works its way down to the bottom i have changed the sensors that is located under neath the coil pack but still left with the same problem and also the heaters work perfect  

Answer
Greg, so you replaced the temperature sending unit? It has a 2-pin plug and a brass 17mm or so bolt going into or around the area of the thermostat housing? From my personal experiences with dealing with this issue on a variety of Honda's 80% of the time it has been the temperature sending unit. Now UK models could have multiple sending units in a variety of locations. I have never even heard of a 1.4L engine or seen one for that matter. The other 20% of the time the problem resided in the gauge/instrument cluster.