I have a question concerning my 05 f-150 fx4. It seems to have a weird chattering when i barely touch the gas. I can hold it just under 1000 rpms and that is when it makes this sound. If you drive it in an area where there is a good echo, example: an alley between buildings, i can barely touch the gas and this sound drives me crazy. It is nothing vibrating, im sure. The dealership told me it was the phasers, but after hearing some of these noises on youtube, nothing sounds like mine. My truck does not run bad at all, just hoping someone else has this sound. The sound seems to be coming from under the truck and not on the top of the engine.

 

Could you have a muffler going bad?

 

its not your muffler its valve train related mine does the same damn thing, sounds like crap in drive thru's or shopping centers. i was also told phasers. the ones i herd on you tube were very bad ours are only starting. i herd its like 1000-1300 to fix if anyone knows a better answer i also would be thankfull. how many miles are on you truck?

 

Dang... I was just out in the driveway with my wife to help me find this exact sound!!! I've heard it for a long time but could never find it and just happened to have the wife with me and got her to barely give it gas so I could find it. It was expecting to find a loose heat shield or something simple like that but it sounded like it was definitely coming from the motor above the catalytic converter. I really need a stethoscope to trace it down. I came online to do some research so if you guys find anything please post the link.

 

most likely the noise is due to the cam phasers. especially if you have a 2004 to early 2006 5.4 3v motor.

You should also check your exhaust flanges. Some trucks have issues with the #7 and #8 cylinder bolts rusting off/through. this causes an exhaust leak. which can sound like a chattering/clicking at low rpms. a minor exhaust leak will seal up when the motor is hot and make noise when cold...until the leak spreads of course.

if you have a leak, you will see a black carbon build-up around the edges of the exhaust manifold. might need a mirror, but it would only take a minute to see if that is the issue. make certain to check the back cylinders carefully.

 

this sound is not like a leak its like parts are loose in the motor. i want to know if i pull the valve cover if i can do anything to make it stop besides a major teardown?