I have a vs commodore ute series 3 v6 had a trailer on was a fairly hot day as im in brisbane pulled up back at home to grab some stuff cam back out and over flow resivour was dumping coolant on road so i poped bonnet had a look pressure in the resivour rose to near the top so i let it cool down and went back to min level so pretty drained over flow engine was fairly hot fans was on i checked see if had done a head gasket but no coolant in oil oils still clean no sign of using coolant as raditors still full so next day started it let it run ides now like a dog no smoke or steam coming from tail pipe now it drops idle from 1000rpm to 0rmp then back up to 1000rmp visa versa until stalls threw the engine light checked codes was unstable voltage to coolant temp sensor and another one for the coolant sensor if rev it over 2000rmp it is normal can anyone tell me whats going on here ? Im changing coolant temp sensor on wensday can the coolant sensor cause this problem any help is apprecated thankyou