I did it , i was looking in the wrong file, Ive got the content.php and change it exactly as you suggested and it works now , thank you very much.
my theme is Cicero from MH Themes.
I did exactly as you suggested, found only one <?php the_excerpt(); ?> in a php file, Ive replaced it by
<?php if( is_sticky() ) {
the_content();
} else {
the_excerpt();
} ?