3D modelling in MAYA..

Here is my concept car and I came up with basic body modelled.... This car is two seater car (front and back) can drive by both person.

I faced a problem while I'm modelling my car in maya, this weird line appeared suddenly and im trying to fix it but its not really working. any idea guys for fix this issue please ? 

I found double faces in my modelling....I'm not really sure whether to just delete or there is any other proper way to remove it ? so, if anyone know the way removing double faces please let me know guys. thanks.