Help! I have a 2004 f-150 Lariat 5.4 with 108,000 miles. For several months, I have been dealing with a annoying hum or buzzing noise only when I accelerate. There are alot of threads dealing with similar noises, but they all lead to different issues. I know that tracing noise problems can be tricky so I will try and paint a picture as best I can.

-It doesn't matter if engine is cold or warm.
-It hums while accelerating and will immediately stop when I let off the gas.
-It will start again when I press the gas.
-It will stop and go quiet when I reach my highest gear.
-The engine idles fine.
-It is not related to anything in the rear axle assembly including rear end, as
I have has all of this replaced recently and the noise is still present.
-I have checked the front wheels for play and they seem fine.
-I have had the transfer case and front diff fluids changed about 10k miles
ago.

Any help would be appriciated on this. I would love to have some sort of direction before taking it into a shop blinded.

Thanks so much,

Derik

 

Air intake noise?

 

I had something like that my intake going into the fender had popped out.

 

Hmm - leaves in the intake tube between the fender and air cleaner?

 

Really, Air Intake? I was thinking it might be transmission or torque converter problems. i'll look into the air intake.

 

only does this with it in gear or truck in motion?

can you get it to repeat, in Park or Neutral in the drive way & slowly depress the gas like you would normally accelerating ?

 

Put it in 4x4 and see if it stops.

When I changed the spark plugs in my truck I got a defective one and had a miss. When I'd accelerate it was hummin and buzzing just like you described. I could tell it was coming from the front end. When I put it in 4x4 it would stop. I'm assuming my problem was something to do with vacuum and the IWE. I changed that spark plug and haven't had an issue since.

I'm not saying you have a miss but it could be a problem with the IWE's.

 

Update: It only does the noise when in motion( not revving in the driveway), 4x4 doesn't seem to matter, and pulling a load up a hill makes it worse i believe.