first noticed it last week while truck is parked/idling. seems to be coming from driver side's front end although not entirely sure. i thought i heard it from the passenger side as well. rattling appears at random times. i just experienced it again pulling into my street earlier: from main road took a left turn, swerved a little to the left to avoid a pedestrian while going at 5mph, and then rattle appears as soon as i straightened the wheels and i could hear it clearly. both windows were down, but i was sure i heard from driver's front end.

info that might help:
- truck is at 52k. maintained on timely manner
- replaced break pads at 45k (myself)
- tires changed from 235/70 to 265/70/17
- engine compartment appears to have no loose cabling
- driver side oem side step currently not installed although brackets are still on (had to use driver side for passenger side in the meantime since the passenger's side side step got damaged from recent accident)
- been pounding on body panels (fender, bumpers, rocker panels, etc) but could not simulate rattling
- no AS installed

please help

 

try banging on the exhaust or shielding. Catalytic converter shield, etc.

 

i just did some troubleshooting earlier. went underneath the truck and started knocking on anything metal. didnt really think much of the cats, exhaust, and shielding so i did little knocking on those. everything seemed secure. still couldnt simulate the rattle.

so i took the truck out for a spin to try and listen to the rattle. i found out that it does it when the engine "vibrates". i mean, my truck is manual so i have to balance gas and clutch. the rattle often appears at a point when the engine is about to die and then you just give it a slight of a gas. the case is often from shifting 1st gear to 2nd or when reversing. this is what i meant by engine vibration (or more like shrudder).

went back into the garage and did the testing there (reverse, forward, reverse, etc.) i could swear the rattle is coming from the engine bay. could it be any of the pulleys? ill check again tomorrow under truck.

 

I have a 5.4, and once the intake tube that connects to the side fender well came out of the rubber grommet in the fender and vibrated like crazy at random times, with a metal sound and all.

I don't know how your intake is laid out, but it's something else to think about checking.

 

Ive been having the same thing in my truck, still havent found out what it is yet either.

 

i think i may have narrowed it down. i asked my bro to play with the gas/clutch while me and another bro stood by the engine. we all agreed that the rattling came from the top of the engine, specifically around the throttle body/egr area. i took the intake off the throttle body and lightly tapped the valve/flange. it's almost the same rattling noise, but not entirely sure. is there an easy fix w/out having to replace the whole throttle body? or is there any place around that area i should look at?

 

I've got the same problem with my truck.
It doesnt happen every time i drive but when it does happen it always happens when i am going less than 10mph, sometimes it stops if i put it in park or neutral and sometimes it doesnt. still havent figured whats causing it...but i think in my case it's the exhaust

 

The only rattle i ever had was from my heat sheild hitting the frame, but it was at startup, idle, and low speeds.

 

i have this also.. 5.4 engine about 75k miles... it could be,

brake dust shield rattling,

IWE solenoid failing and hubs are engaging and grinding at low throttle/vacuum <-- i'm sorry i really dont know what i'm talking about but that sounded good

or most likely an exhaust leak, im thinking im leaking at the cats or manifolds or something

 

what heat shield

 

thanks for the inputs guys. ill check those areas over the weekend when there's plenty of light to be sure and eliminate other possibilities.

basically, i experience the rattle:
- in neutral, especially if the A/C is on as it adds more workload on the engine, and then lightly tapping on gas;
- when reversing - trying to balance gas/clutch and reaches very low rpm;
- changing between gears (deceleration and acceleration) at a very low rpm;

and mengela i tend to be like that often especially in my field of work

 

vibration dampener?

that black metal piece was causing it all this time. it vibrated enough over time that one of the nuts that hold it in place along with the exhaust manifold loosen up. no more rattling!

 

Finally found the cause of my rattle on my 5.4. Intake tube had moved slightly out of place and was vibrating against the inner fender sheet metal on acceleration. Took it out and with a little trimming where it was rubbing it will never happen again. Man was that noise annoying!