I have a very slight misfire or vibration @ idle ONLY.
I have checked the engine mounts.
The truck is NOT throwing any codes.
The only mod is an aftermarket SIDO exhaust.
The misfire or vibration is there cold or hot.
Is this something I should worry about, or is this considered "normal" ?

2005 5.4 XLT Supercrew

 

How many miles on your spark plugs?

 

5.4 3Vs idle rough. Just the nature of the beast.

That said, yeah, if you haven't done plugs recently, they can only help.

 

And clean the throttle body.

 

53,000
I'm pretty sure they are the original plugs.
I got a CARFAX when I bought the truck last year, and it never mentioned plugs.
It DID include such trivial service records such as wipers,though.

 

Speaking on a 2v 5.4, i also had a vibration at idle and changed all the plugs out just recently and it helped smooth it out almost perfect... It actually helped a lot more than i though it was going to..Hope it helps

 

Ford is recommending 60k plug changes on the 5.4 3V, so you are getting close. Be aware of the sticking and breaking issues.

 

You’re probably in line for a change of spark plugs. If you can do it yourself you’ll be able to get it done at almost half the price.