So i have a 04 tacoma 2.7L, shes got 267,000 miles, and nothing has ever been changed on it (besides oil, brakes, minor things). And recently i noticed that when my engine is at moderatly high rpms (not very high) the temp gauge will go all the way to the top (overheating side), and if i let off the gas and let it sit in neautral then it will slowly go back down to normal. Just driving at normal rpms it starts to rise on me.
However i dont notice any difference while driving it, and i put my heater on full to see if it would help, and it barely made a difference if any. Also the air coming out of the vents was like luke warm.
Any ideas what to do?