cliffyk

Sounds to me like something got down into the blower, I had a '64 Corvair that I had to park outdoors and was always getting leaves and small twigs down into the blower...

HorsePower99

Of the three Mustangs we've had in my house, a 94, 97, and 99 all with well over 30k miles(mine has 115k), the countless people I've known with Mustangs, and in my year working at a Ford dealership as a technician I've never heard of this thud in my life.

smitty2919

^it's not loud, if you get in and have your radio on you wouldn't hear it/feel it.

DrewZFoster

My 01 does it too! when I push the clutch at the way in.