Hi everyone. I have a 2004 sentra s model 1.8l. 2 days ago my engine started to sputter. It starts up just fine. Accelerates just fine. No misfire at all. No hesitation in engine. Then after about 10 to 15 minutes it will start to sputter and shake engine. If I let it sit until it cools off it is fine again. Each time it takes about 10 to 15 minutes and it does the same thing. Anyone have any suggestions as to what is wrong?