From spongebob movie sponge out of water
what is that brownish white sedan?

Behind that mercedes benz suv, that is where the unknown sedan is.

looks like a Mercury Grand Marquis or a late 90's Cadillac DeVille but the pic is really small and i'm losing quality when zooming

Might be a lincoln town car or mercury grand marquis. In imcdb, go to spongebob movie sponge out of water and click on "mercedes benz glk350" and that unknown sedan can be zoomed in a good view, little blurry.

after following your suggestion i'm pretty sure that its a 2003+ Lincoln Town Car as its the only one that the grille goes so low in the bumper compared to the Grand Marquis. You have good eye, maybe i spent to much time without seeing a DeVille....