I have a 5.4 24v engine in my 2004 F-150 that has a humming noise sometimes when I slowly accelerate. It sounds like a four barrel carb kicking in but no extra power. If I let off and accelerate again it works fine. If I push the peddle down farther it passes and accelerates fine. I have cleaned the MAF sensor with spray cleaner no change. I pulled the throttle and spacer off and cleaned with no change. Sometimes the engine will increase 200 RPM's and back to normal over and over again(8 to 10 times). Any ideas before I throw in the towel..

 

This happened to mine too. Try disconnecting your battery to reset the ECU. It seems to have something to do with the shift patterns and how the truck learns your driving habit. This seemed to work for me.

 

Disconnected the battery for about 15 minutes. Seem to work but it started back today same thing not all the time just once in a while.

 

Ever a fix for this issue? Mine does the same thing when at cruising speed and getting into it slowly to accelerate. Sounds just like a 4 barrel opening.....

 

Not yet. Still makes the noise. I think it may be the MAF but to cheap to change it.

 

Don't have to change it. Just clean it!

 

I've had a Idle air control valve make the same noises. Replaced it with a new motorcraft. Problem solved.

 

No IAC on 04+, they have electronic throttle.