So i've decided to finally address this issue. my 1997 f150 with a 4.6 is making a noise that is only made during WOT above approximately 4000 RPMs. The noise is what i thought was just the timing chain getting loose but from all the videos i have seen on you tube of timing chain problems it sounds nothing like this; its a metal on metal ticking or rattling noise, very hard to describe. unlike all the problems with timing chains it never goes away. the more strain the truck is under in what ever gear doing whatever RPM the louder and more noticeable the noise is, i.e. pulling a trailer up a steep hill loaded with about 2000 pounds of wood at about 2200 rpm with the pedal to the floor the noise was the loudest i have ever heard it. I'm wondering if the noise is a timing chain about to let go and break and send valves into pistons or just a bad chain tensioner. I have heard that when the timing chain is going out that the actual timing will be off and with 149,000 miles it runs like a sewing machine and never has let me down even after being put through alot it starts and has power like it should. ANY help would be greatly appreciated. Thanks

 

Have you gotten under the hood and tried to pin-point where its comming from? If its right under the valve cover it sounds like it could be a lash adjuster.

 

no i havent because its silent at idle. i mean completely silent. only makes this noise during the conditions i described. wont do it unless its in drive

 

OK I didnt see anything in your post that said ONLY when your in gear. So your saying that reving the engine in neutral does not yield the noise.

 

Could this noise possibly be related to the flex plate?

 

yes i am saying it only happens in gear. i can hit the rev limiter in neutral and the only sound it makes is over revved engine sound lol. but it also doesnt do it as loudly when i am in 1st gear. i.e. 2nd or 3rd gear entering the interstate and pulling out into alot of traffic that's moving quickly it does it loudly. but if its under alot of strain in drive it will make the noise in first gear. i'm just concerned because this noise has gotten louder over the past year or so....and in general the sound is from the front of the engine mostly on the passenger side too.

 

My 2004 with a 4.6l does the exact same thing as you're describing, did you ever find out what it was?

 

yes i found out that it is the timing chain. or more specifically the timing chain tensioner, a common problem on explorers and not as common on f150s