My parents have a 2007 Saturn Vue today it wouldn't start. It was turning over but the engine was not starting. After a good bit of trying to start it the engine finally fired up. The exhaust was putting out a lot of smoke and it kind of smelled like something was burning. I popped the hood but there was no smoke or smell coming from the engine. The car didn't throw any codes. My question is do you guys have any idea what the cause may have been?