This has happened about half a dozen times while accelerating. It sounds sort of like it's between a scratching noise and a rattling noise. It's only happened at highway speeds 50-60 mph while accelerating and will stop when i let off the gas. there have been a few times that i can get it to come back if i step on the throttle again, but will not duplicate every time. any ideas?

 

Can you describe where the noise is coming from? Im wondering if its the same issue Im having that is a knocking/tapping from the passenger side of the engine when its 50 degrees or colder. The higher the RPMs, the louder it is

 

sounds like the front left wheel well, but my dad was with me and he said it sounded like the front right wheel well when he heard it. To me it sounds like someone shaking a tin can full of screws almost, not really a knock. I haven't noticed it in comparison with the rpm's. Just seems odd that it goes away when i take my foot off the gas. I was reading a current thread on someone's cat coming apart. The only thing i can think of with it going away when i stop accelerating is it has to be engine/exhaust related.

 

It could be pinging if you hear it mostly during heavy acceleration. You should try filling up with the next higher octane and see if it goes away.

 

i'm 99.9% positive it's not pinging, i might crawl under the truck today and see if there's something i can spot near the exhaust or brakes.

 

The only other thing I had that's similar is on an old Jeep. The motor mounts were shot. So under hard acceleration, the motor was twisting enough that something was hitting the cooling fan. I seriously doubt that's your problem.

 

i sure hope not, it's not even a year old

 

I have a 2010 Screw XLT and I believe I am having the same issue. About a week ago accelerating from a stoplight somewhere around 30 mph a strange noise came from what I believe the trans/driveshaft area that sounded like a can full of screws rattling. When I let off the gas it stopped and did not repeat. Then today it did it again. When I attempt to replicate it I can not get it to do it. It has a similar sound to a loose heat shield or something rattling. I went under the truck and could not find anything loose. I truck only has 2K on it. Have you found out anything else? I live in cold climate. I want to be able to get it to replicate before contacting my dealer to have them look at it. Is yours only at highway speeds? Mine has only made the sound under 45 mph. Also, there are no issues with the engine or shifting of the trans, they seem to work smoothly. (5.4)

 

I've only noticed it around 50-60mph so far. I have yet to find anything wrong myself and have not taken it to the dealer yet. If i do figure something out i'll be sure to let you know.

 

I am having the exact problem. On the gas near 60mph I develop a rattle like marbles are rolling around in a can, I step off the gas and its gone. Only happens at high speeds. I only have 3k on the truck and its a 2011. I put a MBRP exhaust on it a month ago and have gone under 3 different times to check the exhaust did not come loose and there is no way I can make it any tighter, its not moving at all so I am lost as to what the sound is, ive checked the heat shields, no issues with shifting either....my thought was a rock in the rotor but I should hear that at any speed and should have been gone by now......

Adam
2011 f-150 STX 4x4

 

Did this start after you did your exhaust? Just thinking out loud, I have a rattle at a certain rpm with my dual side exit on mine. I hear it when I start the truck when it hits a certain rpm and when I pull out the drive I hear it sometimes. My exhaust is also tight and was professionally done, sounds like a can of marbles. AWQ134 did you ever figure out anything with yours?

 

Squirt some lube on the exhaust pipe hangers, all along the tail pipe. Thats a rubber/metal combination and it moves.

Y'all have 4x4's? OP doesn't specify. Check hub locks, center caps on wheels, lug nuts.

I think you're hearing an internal heat shield/flange or something inside the exhaust pipe. Could be in the cat, resonator, or muffler. Those of you at low speed, could be the hanger rubbers.

 

D8chumley: I have not found a fix yet. I do have a 4X4, have looked at front hubs(what i can see), don't see anything obvious and they don't have hub locks, lug nuts are tight, nothing in exhaust is loose or rattling. It's definitely not an exhaust noise, it is directly related to the accelerator. I've have a few people mention it being related to the vacuum system having a leak. Something about a small leak and when the engine is under a load, one of the front hubs is trying to engage. Not sure if that makes sense or not.

 

Updating my info, I have checked all parts on my truck, lubed everything however my truck is 3 months old so feel this is not nessicary. Checked all heat shields, then gave a call to MBRP and they believe its a bad muffler and are sending me a new one. I told them that the sound seemed further up but they are confident they sold me a bad muffler so I will update once I get the new one on.

 

hope this fixes it