Hi Scotty,

I need some advice.  I have a 2006 Ford F-150 FX4 that recently in the past few months began having a scratching/scraping noise coming from under the truck only during acceleration.  The noise gets louder the more I accelerate.  The noise is similar to the metal on the brake pads touching the rotors when the pads are low.  My truck has 194k miles but the transmission and engine were both rebuilt at 184k miles.  I took it to my mechanic and he diagnosed the noise to be an exhaust problem.  I took it to a muffler shop and the tech said that there was nothing wrong with the catalytic converters, exhaust, or muffler.  I then took it a local Ford Dealership for a second opinion and they had the same diagnosis that it was an exhaust issue causing the noise.  I took it to another muffler shop where I had both catalytic converters and the entire exhaust system replaced.  I spend over $2k for the repairs and the noise was still there.  I had the tech put the truck on a lift and put it in gear while another tech was listening for the noise below.  They did not hear the noise.  It appears the noise only occurs when the truck is on grounds.  Please help with any advice.  Thank you Scotty!!!