Hey i changed my spark plugs the other day in my 2005 f150 with the 5.4 in it and the whole part of the spark pug thats in the engine was rust and i could see in there was rusty. after i changed them all now when my truck is just sitting there running there is a knock or some thing like as if the engine is running right the truck still hasnt thrown any codes yet help pls thx.

 

carbon build up is plenty normal. Are you sure you used the right plugs? Are they all tight and did you make sure all your connectors are properly installed? Those stupid connectors have broken on me before

 

Carbon and rust buildup on the shank is normal. tell us more about what you did to change them. Did you follow the TSB, did you remove the injectors, did any of them break? If any broke, is it possible some ceramic was left in a cylinder? How many miles on the truck?

Pay close attention to what is going on as the 2005 is prone to injector failure.

 

I changed them how i changed every other spark plug i have a bumper to bumper warranty on it still i wonder it i could be like i dont know whats wrong and play dumb.

 

They will probably check your plugs at some point and will notice that they've been changed... since they'll come out EASY! Hopefully you have a dealer with a reputable service department who will treat you right.

 

if the truck was running fine before the plug change then you need to re trace your steps. I did a plug change and it started misfiring. after i finally got a check engine light it turns out that one of my spark plugs actually broke, but in a weird way. The porcelain actually detached from the inside of the plug and was freely floating in the shield so it would cover the electrode and prevent the spark from being exposed. Weird ish

 

That was a mistake. You are very lucky you didn't break any - or did you?

 

Came close i think but no i didnt.

 

does it knock the whole time? high rpm? low rpm? idle? and can you hear where its coming from?