I have a 05 fx4 5.4L with 85k on it. It has started ideling rough when i come to a stop light or slow down to 10 mph or less. It only does it once in a while. There doesn't seem to be any real pattern. The motor shakes until you rev it up and then it goes away.
I have cleaned the maf, put in new air filter and fuel filter. And put in a new battery.
Has anyone else had this problem? Would a coil act like that? Maybe plugs? Or a vacume leak? Any input would be great! Thanks
could be any of those - have you replaced the plugs yet?
My truck started to have an annoying little miss like that after I changed the plugs.
I had a small hairline crack in one of the new plugs. Wasn't throwing codes but I could feel it. I finally had a dealer diagnose it for me and they found the #8 cylinder was the problem. It eluded them for a while too.
They pulled the plug and looked it over real good finding just a tiny little hairline crack.
1 more new plug and it runs like the day I got it (with 12 miles on it.) Today it has 100003
Mine was idling like crap. It just got slowly worse over time. My radio antenna was jiggling a good 1/2" at stoplights if that's a good indicator. I finally swapped out my plugs at 68K and it's smooth like silk now. They were visibly worn and the gap was about 2x that of new ones. No way they would have lasted until the factory spec of 100K if you asked me!!
yeah its a pretty ****ty design but i think every motor out there has its issues. it wont deter me from buying a ford again, im just gonna do more research up front so when i buy my next one i know what to expect and what preventative measures to take. Im shocked though that this plug issue is so bad. how did they not see that coming.