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

 

did you do your own plugs? did you have any issues. i can do plugs but kinda worried about the breakage.

 

Yes and Yes
I broke two - buy the tool (or borrow one) and follow the TSB it's a bear but it was better for me than spending $600 for the dealer to do it.

 

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.

 

It's a good truck. No regrets for me. Wife liked it so much she wanted it, so I bought myself a 6.4 diesel

Every car I've had has had their own quirks. It's somewhat expected, so don't let that deter y'all

Since driving the 6.4, I'm a diesel convert... No more gassers or sparkplugs for me!

 

does anyone know where the best place is to get that spark plug removal tool. can you get it at a auto parts store or is it a special thing

 

Napa, or buy online
Summit has them - a quick search even turned up Amazon Amazon.com: Lisle (LIS65600) Broken Spark Plug Remover for Ford Triton 3 Valve Engines: Automotive and thats about 1/2 what I paid.

 

I have replaced my plugs and the idle did not get any better. I have cleaned the MAF still rough idle. It hasn't threw any codes. It seems that is getting worse. Any more suggestions?

 

does yours only do it when its been running a while ?

 

No it is a constant. From start up to cut off. It is getting really annoying.

 

Were any of the plugs fouled or more sooty compared to the others? That would be an indication of a bad coil causing a weak spark

If the EGR valve is stuck partially open, that would be a cause of rough idle also, but these days, I'd think a CEL would show up if that was the case

 

Tool works great! Highly recommend. Just read instructions and be sure not to turn it in to far. Took me about 30 min. a plug...

 

Thanks aquaman. I really didn't pay attention due to the fact of them twisting off in the head. I then went into panic mode. Then I had to buy the tool.