Started my Porsche Cayenne S (06) today and it seemed having a little difficulty starting. Once it did start, it shook a little and almost rumbled. Never experienced that with it before, and it's very hard to explain. I shut it off instantly because I was scared to run it. After 10 more minutes I started it again, and it seemed to start a little more easy however it still shook a little. I opened the door and a smell hit me that I never smelled before. The smell didn't really smell like gas or oil, the smell was hard to explain and it was coming from the engine. I let the engine run and there was a silent ticking sound coming from the engine, I shut it off again, and didn't start it again. Does anyone know what is wrong? What do ya'll recommend me to do? Should I drive it to the dealership? I'm afraid to start it again.