i'm having the same issue! in my integra, i've took it to a few shops and they did a leak down test, etc etc. and they couldn't find out what the problem was. And was referred to replace all the temp sensor, fan switch, temp sensor on computer? i've replaced all the sensors and still does the same thing. But only difference is that i took out my thermostat and so far so good! so prolly the thermostat was not opening up in time or etc. i havne't drove it for no more then 20mins but hasn't overheated yet! i'ma have to take a cruise up & around atlanta 1 day to find out. But i cant do that just yet, because my engine is acting up now and thats the delay i'm having ... You Fix one problem, another problem occurs! WTF.. my next car is giong to be a KIA!!