Car smells like gas

You either have a fuel leak or the engine's got a bad enough misfire that fuel is going out the exhaust. Open the hood and look for an obvious fuel leak. Or better yet, tow the car to a Nissan specialist to get it diagnosed. Fuel leak is a fire hazard and I wouldn't want you to burn the car and yourself up for no good reason. Here's a directory link for you: http://repairpal.com/nissan-repair-in-stevens-pennsylvania