So last night I was sitting in my truck talking to a couple friends when I decided to throw some revs, and when I did I would herd a loud metal on metal rattle type noise that would disappear as quickly as it appeared, anyone know what this was ?

 

follow your exhaust and look for a broken hanger

 

Will do this tomorrow after work and let you know.
Any other suggestions ?

 

My guess is you are running a chambered muffler like a flowmaster? broken baffeling plate perhaps?

 

i had the same sorta sound in mine turned out to be the cat somethin had broken loose from inside it and itd rattle id do what thejake said first then that. cats are warrantied for like 80000 miles though at least my ford dealer said that

 

Yup, that could be it, i thought he had an aftermarket system.

 

I guess I should have stated that, it's a complete stock exhaust system as of now, and I've herd of cats breaking like that but isn't the noise a constant rattle when this happens ? it only happens when I rev it quickly and high, it makes a "ting-tuh-tuh-tuh-ting" noise then shuts up as the revs come back down.
Hopefully it's just a hanger, I hate going to dealerships.

 

What year is your truck. 97-03 2v 5.4L's had common issues with broken studs on the passenger side manifold. causing a leak. Sounds like thin metal slapping. I've had it on both f150's Ive owned. My dads leaked, co-workers leaked.. etc. Pretty common.

Either way, have someone rev it up... while you pinpoint the sound.

 

Check out your catalytic heat shields first.

 

I agree with darren heat shields happens quite often

 

it's actually an 06, I guess next time I'm going to have to be more specific about my ride. Hopefully I can get under it tonight if I can find some dry ground, I really don't want to get wet.

 

That sounds real similar to and issue I have been having. I only get it on start ups when the truck high revs usually first thing in the morning. It might do it if I reved up the motor I had not tried that. Anyway I have suspected that it was coming form the drivers side cat but I thought maybe some pebbles were in the heat sheild? I just have not had the time to get down there and search yet. I only did a muffler swap so my system is basically stock.

 

so I just got back from outside, and I cannot get my truck to make that noise anymore.... got under it and the heat shields are firmly in tact, hopefully it never comes back and I can just drive it

 

Thats exactly what mine was like when i had this issues but my dealer replaced the whole cat so im not complainin

 

If it wasn't the heat shields or a broken hanger, I'd probably say it's the cats. Does your exhaust smell richer than you're used to smelling? (Don't put your face up to the pipes now...) My cats are shot right now, and apart from the terrible noise, Gas mileage went down too... I gotta start working again...