Nasty Ticking fixed & What could have done this to MY plug, too? with Pics
 

Ref: the thread about the broken electrode in this forum -

yesterday my truck would barely run as I limped it to the shop (appointment to replace the muffler). The mechanic removed the #3 plug per the CELs.

https://www.f150online.com/forums/me...0-badplugs.jpg

i'm fixin to replace the lot of them - but fixing this plug solved 80%, 90% of whatever ticking I'd heard previously.

The Mechanic said the plug was loose and wobbly. The replacement plug fit fine.

What brand plug was in it?

I can't tell - but I can read ZH and 4F written on the ceramic.

Sounds and looks like it either worked loose or was never tightened properly

Twas a plug and coil replaced about six months ago by a shop; truck had same symptoms; barely ran. Had the head been damaged I would have brought them a bill to work something out.