I have searched this over and over and cannot find anything on it.

My truck has a momentary moan / growl / bog down issue. It happens at town and highway speeds and usually when I have cruise on OR when I lightly apply the gas peddle. It moans for a few seconds and seems to bog down then comes out of it and carry's on its way. You can hear it plainly while driving even with radio on. I have a regular muffler on the truck but when this happens, it makes it sound like I have a catback on it.
Things i have done...HELP this is getting annoying!

new air filter
new oil/filter
new fuel filter
ran techron injector cleaner through tank of gas

 

A shot in the dark here, look at the air intake before the filter. It could have debris where it comes out of the fender well.

Like I said....a shot in the dark.

Good luck.

 

Just took mine to the dealership last week. Look up cam phaser issues, that is what is wrong with mine. The warranty company is denying my claim but I am fighting it. Apparently it is a common problem with the 5.4, who knew. Most people have said that it can be fixed but some have had to replace the entire engine. They are denying mine due to engine sludge, but I have changed my oil regularly. My problems sound very similar to yours, sorry to tell you the bad news. I hope you have some kind of warranty.

The cam phaser issue is common to 04 - 06 5.4 triton engines. There are multiple threads on it. Good luck!

 

How many miles on truck. Have the plugs been replaced?

 

122k and plugs were changed at 112k
Are there any oil additives that can be added before an oil change to break the sludge up and get all or some of it out of the engine?

 

Really, only Auto-Rx ...

https://www.f150online.com/forums/v8...hlight=auto-rx

99.9% of the other stuff is snake-oil.

MGD