hello,
so back in id say January I was replacing the coils and plugs on my 05 5.4 and I noticed some of the clips were broken so they occasionally come loose and truck thinks its miss firing well now im getting a different code of P0420 and its saying my cat is bad any one think this could be related im getting very many mixed reviews from a lot of mechanics I trust ideas?

 

If the clips are broken and becomes disconnected to the coil the spark plug will not be firing. This gives you the misfire and also lets unburnt fuel through the exhaust valves which in term kill your cat's. It is very much related.

You should replace those connectors or at least tie them down with wire asap before you put another cat on there.

My local dealership was charging close to 80$ per connector! I found the exact same connector from another company for only a couple bucks each.

http://www.corsa-technic.com/item.ph...category_id=55