ok heres the thing,on start up it sounds good,runs good and no noise.but once i start driving it starts,but only when the engine is not on a load...like going down a hill or just easing back on the throttle alittle or turn off overdrive(???)....its weird it does not make any noise going up hills or when the motor is in a strain.it sounds like it is coming from the dr side head.any ideas.....this is the only problem with my truck now.i just got back from a 700 mile trip with no problem,real good power just that awful rattling/tapping sound.btw the motor has 213k miles!!!! and its in a 99 f150 scab 5.4 2wd.

 

Is it possible the noise is a little lower like at the cat?

 

nope,the cats are gone,removed by the po.and its not like a rod knock...atleast not like one i have ever heard,but this is my 7th mod motor so i dont have alot exp with them,never worked on any of them except like tuneups,oil change just minor stuff never been inside one.this is my 1st 5.4 , so these motors have my confused. but i am thinking valvetrain...maybe a cam follower or a wore out cam,i dont know.

 

I had a similar sound happen to me yesterday. I have 202k on a 97 4.6.
I was sitting at a drive thru window waiting for change, with the transmission in park. I started hearing what sounded like a dry bushing sound, and it sounded like it was coming from the left head. But I was sitting inside so that was just what I thought I heard.
But anyway, When I put it in drive to leave the sound stopped immediately. When I got home I popped the hood and listened, and couldn't hear anything out of the ordinary. When I heard the sound the engine had been running only 5 to 10 minutes, and I didn't even crank it today, because I had other projects going. The temperatures here are the lowest they have been in a couple of years(in the teens). I'll be listening tomorrow to see if I notice it again.
I have recently had a noise also that made me think the time is coming for some timing chain maintenance. But A couple of time I've thought maybe I heard a light noise coming from behind the timing cover. I wouldn't be surprised if the tensioners are getting worn. But this has been a great engine so far.

 

well it looks like i'll be replacing this motor.a friend is giving me...yes giving me a lightning 5.4 supercharged motor...everything from the block to the blower all the way to the computer....so i will be doing a lightning swap thread here soon.

 

I was typing some suggestions while you were typing your new plan. Good luck

 

thanks..but i would still like some suggestions on what could be up with this engine...i still gotta drive it for atleast a month before i begin the swap.thanks