I have a 07 Lariat with 5.4L. Has 47k miles.

I just bought it and its the first 5.4L I have owned. Is the idle suppose to be whisper smooth or feel like its missing a bit? Mine feels like its missing abit. Nothing too bad. It starts fine, runs good as far I know. My previous truck was a Chevy Suburban with 5.3L that was whisper smooth, so I notice the rough idle in my Ford.

 

I would check / change all the usual items:

- Change Fuel Filter
- Change Air Filter
- Consider having the plugs replaced
- Run a quality injector cleaner or get an injector cleaner service (after fuel filter change)
- Clean the MAF Sensor

There is a lot of info on these topics on these forums if you use the search function.

 

you can check your throttle body too it may need cleaning.A dirty throttle body will cause a rough idle as well

 

I've had an issue like this twice and it ended up being an issue with a spark plug on cylinder number 3. It didn't seem to hurt the performance much, but it idled a little rougher then usual.

 

I've got the same truck. Mine seems to shake a little at idle. It doesn't run funny in any way, no skipping, no stumbling. It idles steady but every once in a while while idling I will feel a little shake. I wonder if it's the same. My 4.6 never did this.

 

My 05 does it too.

 

Took it to my buddy today. He changed out the fuel filter, cleaned out my throttle body and told me that my air flow sensor had some K&N oil on it. So he did his best to blow it out.

$50 bucks for his trouble and it runs noticeably better.

 

^ did you over oil your K&N Filter?

 

hmm, interesting... seems like a logical potential culprit for me too.

 

I didnt install it. I had a truck accessories place put it in for me and it could be that they over oiled it. My buddy said that it needed a good wiping off when he looked at it. After a week of driving it, idle is as smooth as silk and got 19 MPG on my last HWY trip.