Plan on a catalyst, should be an 8/80 part I think..
28530-38780 CASE ASSY-CATALYST $ 937.13
28535-38150 GASKET-CATALYST CASE $9.41
Add local shop labor, and possible bolts/studs/nuts as required, and gasket ot bottom of catalyst to front pipe..
You stated in previous post you replaced plugs a month ago... was the engine running bad/bucking/jerking/MIL flashing ??But i have checked with the code reader about mis-fire it was ok no mis-fire over heat i haven't experience that before with my vehicle
Meltdown i dont know what you mean with that !!