Truck: 2000 f-150 4x4 7700
Hi this knock came about two weeks ago is sounds deep and sometimes its there on start sometimes not like i drove 15 kms and thought on highway i was gona pop it for sure. then went away no more till 2 house of city driving later did i hear it again.(truck was not stopped at all for that day so did not cool down or anything. the sound don't speed up a lot like other engine knocks when you accelerate, when you get highway speeds if the noise was there it goes away. under load by sppeding up quickly it goes away and some days its not there at all you think oh its gone. then its back.

looked here and is said some different things so this is what i did.
-added restorol to engine and octain boost to gas
-let engine run for 2 hours in driveway
-pulled plug and let oil go hot in gopher hole lol( just kidding in bucket)
-used quaker state 100% senthtic 5w 20 and a ford filter.
-changed the serpintine tentoner pully that i found seased at the same time.

the noise seemed louder doh!
I had a friend mechanic listen and drive it he said probably timing chain slap as it is loose.
or flexplate loose or broken.

the timing kit is $472.00 and tax with 8.1 hours labour so $1300.00
the truch has 254000 on it.

ok questions.
-what is the chance the timing chain is the prob?
-what is the chance the flexplate is?
-if i do timing stuff now whats the normal max kms for this trinton 5.4?
-can i get self installing parts? lol

thanks any help is great.
Tony