I got my plugs changed on Thursday (Motocraft) and on Sunday, the truck ran rough from a few miles then threw a code.
The auto parts store code reader stated in was a misfire in Cyl 2 pending and a misfire in Cyl 3.
Had them clear the codes, truck still runs a little rough and idles a bit rough but no codes.
Took it back the shop who did the plugs and they check all the coil pack connections and really didn't know why (of course it was running smooth when I brought it).
They said to come back if it throws another code and not to clear it.
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Just because they are new plugs, doesn't mean some weren't faulty from the factory. Take it back to them once you get a code and get it fixed. Maybe they just need to be torqued down again. Or maybe you need a new plug in a cylinder or two.
Just had a simalar problem yesterday myself. There on the coil pack itself, I had a cracked connector at the base (was one of the problems I found), so I had to replace it. Just if you wanted to check or have them. It was a small crack but enough to manipulate the metal connectors that run through it.
Last edited by nicks08fx4; 07-09-2014 at 05:20 PM.