Nissan Repair: 1989 maxima, radiator cap, foot on the gas

Question
My 1989 Maxima keeps over heating if i keep my foot on the gas( like driving on the freeway) for about 30 min. I'm i'm in stop and go traffic no matter how long it doesn't overheat. I have changed the thermosstat and even taken it out. What to do now.

Answer
David,

A few things here.  First, if it overheats while driving at speed it could indicate that the fuel you are using has too low an octain rating or the timing is too far advanced.  If it were me I would also purchase a new NISSAN radiator cap.  Buy a factory cap as it is worth the money for what it will save in the long run.  If putting premium in is not an option retard the timing a couple of degrees to get the enging to stop pinging.