rattling sound
 

Need help on a rattling sound that is happening on my 2006 f-150 screw 5.4 only mods are volant cold air intake and cat back exhaust. Sound seems to be coming from passenger side foot well compartment. Its sounds like a spark knocking or tinny sound only when engine is under load . First experiance it when od is off and im pulling a hill with my trailer, Now i seem to hear it when truck is in od and climbing a hill when the rpms go down before it kicks down . This noice is really annoying sounds like the truck is going to come apart. Any help would be greatly appreciatted

I have a 2001 F250 super duty that resembled exactly what you describe, supossedly there is an access panel somewhere on the flywhell cover and it slipped in and is dragging on the flywheel might be the same problem.

Sounds like detonation or lean condition to me. See if it has any codes such as lean or misfire. If that's the case, get that Volant off of the truck until you can get a programmer with custom tunes that'll fatten up the fuel curve enough to get the A/F ratio back where it should be. Detonation eats platinum plugs and can ruin a perfectly good engine.

Torque Converter rattle maybe? The automatic hubs will make noise too when load increases, the actuator solenoids go bad and you'll get vacuum present at the hubs all the time, so when the engine increases rpm and you lose vacuum to the hubs, they'll make weird noises, sounds like a spark knock sometimes.

Any time someone describes noise under low intake manifold vacuum conditions, I think IWE's. Mine sounded like barbed wire wrapped around the front drive shaft.

hey thanks all for your help, just to add one more thing this sound does not happen from a standing start (wot) nothing sounds out of the ordinary . Will try pulling intake this weekend and see if any thing changes . Intake has been on a year and a half and this noise has just started happening. First noiced it pulling the trailer but not notice it on a hill ( not even a big one) when the motor is working hard in over drive and really seems to be getting worse by the day

Be sure to check for codes as well.

Heat shield? Or debris stuck behind the HS?

Rattling noise 2006 F150
 

What was the outcome of your problem. I have the exact same issue and the same mods done on my truck.

99% probability it was the IWE's as it probably is on yours.

my truck is doing this, again. it did it awhiile back and then stopped. what is an IWE? also no lights on the dash, will it still throw a code if you do not get a warning light on the dash?

My problem was a vacuum leak between the IWE solenoid and the IWE actuator. Search on IWE and you will find plenty of info on it. Thanks to all the info it was a pretty easy fix and saved me plenty from not having to take it to the shop! It is the 4WD hub locking system.

i believe i confirmed that my noise is my IWE today. driving to work with the window down heard the rattling and flipped the 4X4 on... noise immediately went away, shut 4X4 off and reapeated a couple more times. every time i flipped the 4X4 on the noise stopped.

now i need to inspect, or thought about just replacing, the vacuum lines before getting into changing the entire unit.

i love this site. great information!

thanks everyone

I had a pretty easy fix. I bought a vacuum pump/tester at the parts store for $40. Tested the first line down from the solenoid to where it branched to both actuators and the leak was there. Seems like the trucks can keep the vacuum good enough to overcome the leak until a heavy enough load on the engine and then then not enough vacuum and you get the rattling sound. Good luck!