I recently bought some humbucker covers for my new Dean ML X because it has zebra pickups and i think they look kind of stupid but i put the covers on and it looks sweet problem is, it screeches horribly at any volume with them on, I messed around with them for a while and figured out that the only one that actually screeches with them on is the bridge pickup, why does it do this and how can I fix it?
You don't mention how you installed the covers or if they are solid or with holes.
In general, you need to remove the outer layer of black electrical tape from the pickup. The you need to "pot" the pickup to the cover to prevent feedback.
This can be done by drizzling about 1/2-1 teaspoon of melted paraffin wax evenly inside the cover before inserting the pickup. This requires that you first remove the pickup.
Proper potting should take care of any feedback problems.