I have an 06 f150 with a 5.4. While accelerating it has a loss of power until about 3500rpm amd then its mostly normal. I have put a new fuel filter and maf in it. Cleaned throttle body and air filter. Tried disconnecting battery amd letting idle until warm and still no improvement. Tried the tps relearn also. It does have the ticking as expected and on cold starts ot knocks for a seccond. Im assuming it is timing chain tensioner seal gone bad as it does have 178000mi. There are no pending codes or anything. Any help is great.

 

Has it been changed . If not have lisle tool ready to extract plugs of orig plugs . I would not go over 60k on a set of plugs .

 

Let's hope with 178,000 miles on it .. it don't have the original plugs in it.|

 

Plugs! More than likely

 

I guess i forgot to add i changed the plugs around 160k and coil packs around 175k

 

It will only do it under load like merging on highway or passing. It is almost as if i am towing a heavy trailer and around 3500 rpm the trailer dissapears

 

Check you cats ..