I need help! Yesterday I was driving to work. Drive is about 10mins. When i got to work i noticed what appeared to be steam coming out of from under the hood. II went and checked my gauges and the temp gauge showed that it was overheating. When I opened the hood there was coolant on top of the engine and the coolant reservoir was empty. I let it sit for my entire shift. Filled the reservoir with coolant. Turned the car on and let it idle for 15 mins. Gauge indicated it was fine. I was 5 mins into my drive home when the temp gauge spiked way up while accelerating. When i got to a stop light the gauge lowered. It seems when i accelerate my temp gauge moves way up but when im slowing down or idling it cools down.

I dont know what to replace? There is no liquid on the engine or underneath the car. The coolant is still full. Last time I had a car overheat I had to replace the water pump, t-stat, and belts.

Here is the tech manual. Go to page seven.
http://psedog.com/cars/fsm/g35/sedan/2003/co.pdf

I would check your thermostat and water pump. If it were your fans then at speed you temp would drop not rise.

Yea. Went to check the thermostat and saw sow there was some water coming from underneath the filler neck. Yup. Cracked radiator. Went ahead and replaced the hoses, tstat, both belts and the radiator.