floorboard & accelerator pedal vibration - Jetta

I recently ran over something that looked like an extra large thumbtack/push pin. The tire did no go flat but two days later, I noticed vibration on the floorboard and the accelerator pedal. The mechanics at VW checked to make sure the tires were balanced, the wheels were in alignment and even looked at the axels but couldn't find any problem (and they didn't feel the vibration, but it's definitely there). Does anyone have any suggestions of where else to look? I've recently had a new catalytic converter installed - might that have anything to do with it?

bent rim?

Did you hear any sort of noise when you hit whatever it was.  Vibrations usually come from rims/tires or somewhere in the steering parts.  Check the tie rods make sure they aren't jacked up.  Something could be loose too, but just put the car on a hoist and move and shale everything that has to do with your suspension/steering in the front of the car.  If you get a lot of play on something then that's your problem.  But def check those rims/tires.

could also be a motor mount, could just be a coincidence that it happened after you ran that thing over.  if not motor mount you should def check the rims and other shizzle down there