Brydon90

Temperature issue. Currently getting issues still with my 2018 skoda octavia vrs dsg 2.0 tsi. I have replaced thermostat water pump belt and temp sensors all with original dealer parts. My car doesnt have a dsg incline thermostat as symptoms all lead to that potentially being the cause but confirmed it hasnt. On idle start up the car temp after 5-10mins slowly climbs to 90. Upon turning blowers on they are hot but within minutes the gauge slowly drops. Once i drive mostly at higher speeds rather then round doors the gauge then goes nearly back down eventually to near on 0. Has anyone expierenced this. After a day or 2 the eml tends to come back on. Literally cannot think of anything else along with mechanic. I tried a aftermarket thermostat previously to a dealer part but no diffrence. Could it be electrical. Its as if a brand new thermostat doesnt want to work. Thanks in advance