I'm looking for a Sci-fi movie title , the only thing I can remember is a guy being chased in the desert and he managed to find a hill-like place to hide his car (his car looks like those in mad max). He finds out that the hill is actually an old kind of base , so he opened the door and fits his car in. Once he gets inside , plenty of fat white creatures comes out of wholes in the wall and ceiling to attack him..

That's all I can think of :(
So I Hope that's enough , thanks :)

Is this it?

Back to the Future Part III (1990) (http://www.imdb.com/title/tt0099088/)

Lol not really.. thanks for trying though :)

Forget the part where he is being chased in the desert... the focus is more on the creatures coming out of the walls and ceiling when he gets his car inside the Base.. which looks like a big Rock actually. His car looks like a dunebugey...

Guess this is just not enough details for you guys to help , kindda sad but still , thanks for trying :)