I had this exact problem, it was a differnt car though! It was a turbo 300 z! It was horrible but wouldn't do it in the driveway, it waited 'till I got into town and stopped at a stop light! I freaked and spent a fotune replacing the turbo, all the vaccum lines, redid the heads, and so on. After almost 4500 bucks in parts and 3200 in labor I got it back, got to the first light and blam, I couldn't see the car behind me! It turned out to be the PCV VALVE!!!! A freakin' $3 part! Hope it helps! good luck!