V1ns

Hey, guys, I just bought a Z, 2005, great overall condition. Mint in and out. Engine sounds smooth, no knocking or tapping. Only problem is CEL, P0420, P0430, which are Cats below threshold. Drives nice, but I found the throttle not being very responsive, and more precisely, it delays a little when step on the gas and also when let go the gas.

Im not familiar with the car and just wonder what kinda stuff can cause it or If it is normal for a Z.