didn't change a thing...honest
 

Any idea what would cause a humm that goes in tune with the rpm's? I haven't done anything, ie...added lights etc..
I checked all of the plug wires, they are fine.
This humm comes through the radio...even checked the antenna to see if there was some rust working it's way in there...it was clean.
this just started 100 miles ago, but is driving me crazy.
any help?
thanks

Alternators can cause a whine. My guess on a hum would be in the 12 volt side of the radio.

Stock radio? You have an amp? What year? Under warrantee?

Radio Shack sells various types of noise suppressors.

You really need to supply more information.

bone stock
 

bone stock 97 f-150 xl....no amp. way out of warrantee..thanks

You might try putting a noise suppressor on the 12 volt line going into the radio. Maybe someone else will have better ideas.

Does the radio act ok other than that? Could be it's going out.