1999 F-150 XLT Ext Cab 4.6 Litre 2 wheel drive automatic 240,000km
I have this whrring noise/ humming in the cab when driving that changes in frequency with the engine rpm.....it's driving me nuts.
I have already ruled out Alternator, clutch fan, all accesories a/c PS/etc..and transmission.
It reminds me of the cars in the 60's when you could hear feedback thru the radio if you had the wrong spark plug wires for those old enough to remember those days.

Any ideas suggstions on where to look and/or diagnosis would be much appreciated.

Thanks for looking.

Cheers,

Jerry.

 

Is it coming through your speakers? Do you have an aftermarket stereo? Amplifier? If its through your speakers, go through and check your grounds, and power connections.


-Matt

 

Hey Matt appreciate your suggestions, the noise is not coming thru the speakers, I do have a JVC radio/cd player no amplifier, noise is there with or with out the radio on. I will check the connections to be sure.

It's kind of a ghostly noise,haunting sound, a tech that road tested thinks it's a vacuum leak under the dash.

 

If I'm thinking about what you're talking about, I hear a humming sound when I give gas and what not. It sounds like it's coming from the ground if it's what I'm thinking. Hopefully I can give you the answer once I sound damp the floor.

 

I had a vacuum leak coming from one hose by my throttle body caused a similar noise. Fixed plastic connection and now have no noise. If not there check any rubber connector spots,like the transmission linkage,transmission mount or maybe the emergency cable rubbing on back tire drivers side.

 

Where is this throttle body located at?

 

It's at the end of the plastic air intake under the 5.4 logo'd plastic cover on top of engine.