Just bought. The car nocks. I put the gas on and it giggles it's making nocks. Took it in. Bad gas. Well I dont know that. I cleared out the tank 4 times. And different gas stations. Only used chevron. 91 best. Or Exxon. 91. And different city's. It still knocks. Porsche is going to bring in and have experts test. It's bad I'm mad I paid good money and don't want a lemon. Help any way possible its something else No engine lite and it's not hurting the car or the linguine light comes on but never. Has. It bad I hate it. What can it be and no one that get gas at the same place has ever gotten bad gas. I keep it the garage so it's not anything like someone put water in my tank. Plus I took it down to empty 4 times halp