My 02 5.4 started getting a lifter knock at idle when it hit around 127,000
I tried putting a half of quart of atf in oil to clean out lifter no change, then I changed over to Ams oil and used their engine flush before I changed to thier product, and use their long duration oil filter and have not heard the noise since, they say you can go 15,000 miles between oil changes on an engine with over 100,000 miles on it but I change mine at 7500. if your having this problem I suggest you trying this it worked for me!

 

mine does the same thing. I was just hoping that there is a fix for it, but it seems to be normal from what I read here.