be sure to purge your cooling system of any trapped air. that will account for uneven temps. do a search on the toyota newsgroups and you will find the correct procedure.
if your toyota has the long block six they are notorious for blown head gaskets although i don't know to what year. if you have clouds of white smoke coming from your exhaust that's a sure sign.
1993 300e-2.8 - gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"