KA24DE Engine overheating help plz?

[jazz4890]

I have a 1991 Nissan 240sx with a KA24DE I am having a problem with my car overheating I let it idle for a while and its fine it doesnt overheat but when I am driving on the streets stoping and going it starts to overheat but when I get on the freeway and start speeding up my enigne starts to cool down very quickly also sometimes when im driving it doesnt overheat and other times it does while I am going fast on the street it doesnt overheat but right after I shift into neutral the heat gauge shoots up towards the H and when I stop the car and turn it off the coolant resevoir tank has a bunch of fluid bubbling in it does anyone know what the problem might be?