Hi.. Thanks for the query.. From your explanation it is clear that there is infection that is causing the bad metallic taste.. It is probably appearing that you either have infection occurring due to seepage of food in between the tooth and the cap or the gum is infected.. Food lodgement is appearing to be the most probable cause.. You need not to get the bridge removed directly and first of all get an x ray done to rule out infection and also bone loss over.. If then it is needed then sorry to say but the bridge might need removal at last to treat infection and then if possible same bridge can be replaced.. Also a deep scaling has to be done.. For now start doing antiseptic mouthwash gargles and also do warm saline gargles.. Maintain a good oral hygiene.. Hope this helps.. Regards.