Hey Guys I have a 2006 F150 with a 5.4L in it and have had all kinds of problems with the truck running rough, either at idle or will surge on hills. The truck started acting up when it had 20,000k on it and the dealership changed out all 8 plugs on the truck, they claim that they had a recall or something on them. And go figure the truck ran just fine. Note the truck was stock at the time. Installed both a airraid cold air system and a 2 1/2" dual cat back exhaust system, still ran trouble free for around 50,000km and then started to pop and backfire when pulling hills or under acceleration. And of coarse the dealership changed out the plugs in it again but this time nailed me $700.00 to change them and this didn't help it at all. I was told to just drive it for a while and it would magically fix it's self. Go figure it didn't, I actually went and bought a COP from ford and went through cylinder by cylinder and found the faulty coil and it has ran good for another 20,000k and is starting to backfire when I really step on it again from the right side. Just curious if anyone else has had problems like this and how the dealer have been treating the rest of you fine ford loving people. I really like my truck but after the service I have got out of these guys around here I'm almost positive I won't be back.

 

As much as you would like to go forever, you was getting 20,000 miles between problems so far.
The parts are getting aged now and you have to expect problems will be more frequent.
The coils are a problem, unless they outright fail and set a code; you cannot easely see what is happening and which ones are causing the problems.
From experience, some cases require a dealer stress test of each coil to find the ones that are causing drivability problems.
You can even get into a problem replaceing all coils and still have drivability issues if one or more of the new coils are defective and no codes to give an indication. This really gets involved and stressfull for some but this is the way it goes for some owners.
You have already saw that replacing parts and hoping for the cure does not always work.
Also with a back fire, fuel problems can cause this.
I would check fuel pressure first, suspect possible injector problems.
Again a dealer can do testing for these malfunctions.
We all have the problem of high dealer costing but they have the special tools to do these things when we find we can't handle the problem; then some dealers have a problem with expertise doing it.
I wrote this reply to get you to see a different perspective on the reality of all this because we all have to deal with owning a complex modern vehichle when things go wrong.
They are nice to own and run when all is new and right but you really see what it's all about when problems come up, the hassle and expense it causes.
I could go on about a lot of things but will have to leave it at this.