Hi all. My '01 LC (281k) is overheating after the heater tee blew. Temp never got into the red that I saw. I replaced the tee and filled the coolant system. At idle, no overheating problems but I am getting misfire codes on cylinders 2,4&6. When I drive, the temp climbs quickly a few minutes in so I've pulled over and let it cool down then drove back home. The upper radiator hose is under a ton of pressure like it isn't circulating coolant. I replaced the thermostat and nothing changed. Water pump and radiator were replaced by toyota along with the timing belt etc last summer. Idle temp is between 176 and 184. No white smoke from exhaust. No milky oil or pressure coming from oil filler tube at idle. Any advice other than a compression check to see if a head gasket blew? Thanks for your time.