so ever since the cat has been gutted, the car develops strong shaking at certain low rpms... it usually happens when i am barely giving it any gas, but it shakes the car quite a bit... feels like exhaust, but who knows? the car did not drive very well before i got all sorts of work done to it all at once, so i am not sure what exactly is causing this shaking, but i would sure love to figure it out...

 

Probably misfiring. Check engine lite lit?

 

nope, no check engine
also, why would it only misfire at low rpm? its fine otherwise and wraps up to red line ok

 

its your opti. 99.9% on this one