Adding expiration date of post

Hi,

My new post are automatically tagged as “Archive” just after the publication and are not listed when checked in Google (but after clicking for excluded links).

I can’t see them as new post in Firefox. In Opera I do.

When I select category of the posts I can see them enlisted with “Archive” tag.

I want to set expiration date of post and change the loop:

<?php
if (have_posts()) :
while (have_posts()) : the_post(); ?>
$expirationtime = get_post_custom_values(‘expiration’);
if (is_array($expirationtime)) {
$expirestring = implode($expirationtime);
}

$secondsbetween = strtotime($expirestring)-time();
if ( $secondsbetween > 0 ) {
// For exemple…
the_title();
the_excerpt();
}
endwhile;
endif;
?>

Please tell me which file exactly I can change and which text should I replace?

Recently I plugged some cache plugins WP Fastest Cache, LiteSpeed Cache and this could be the reason why the problem arose. However I would need these plugins.

Thanks for help!

Adam

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