2000 z28 throttle sluggish to respond

[Sleeper101]

We just bought this camaro, It has 3 engine codes on it. egr valve, o2 sensor and a catalytic converter code. it does not have a catalytic converter on the car. Someone has replaced it with a straight pipe. It runs great no issues hot or cold. But the throttle seems sluggish. Seems like you gotta push it down 1/4 throttle before it responds. I drove a buddies 2001 ss and it responds instant, So what would cause it to be so slow to respond?

[Knight]

A4 or M6?

[Sleeper101]

its a m6