Speed dependent 'whomping' sound

[Supermoney]

These past few weeks I have noticed a new sound / feel through the floor. Can really start to notice around 30 mph, its almost like a 'whomping' or like when a wheel bearing goes bad, however I had them both replaced last year. Sound doesn't really change when going left to right on the highway to try and replicate it (for wheel bearing).

It is speed, not RPM dependent. No changes when shifting into N while driving. I can really notice it at 30 mph as well as 60 mph.

I can very slightly feel it through the floor / pedal. Really not sure where to begin.

I can almost rule out the tires, I will be having them rotated in a week or two, but fairly certain it is not them. They are E rated KO2s with 30k miles on them. Wear is perfect. Still lots of life left. This noise just started randomly about 2 weeks ago.

Anyone have a clue?

2002 Sport, 231mm brakes, trans cooler, supercharged, 33s, etc.

Thanks guys.

 

[Plastics guy]

Drive Shaft!

Check your U-joints...

I had the same problem. One thing that i did notice and have read in other drive shaft related threads is that when you let off the gas pedal the vibration goes away. I didn't see you comment on that. op2: