>>4237774There's nothing wrong with the camera.
I think you really need to improve your shooting technique (ie hold the fucking camera steady) or the lense may be dropped, broken, just never that sharp in the first place. I mean it's not a cheap lense, but it's still a zoom, and designed a long time ago for full frame cameras, so it probably isn't really going to deliver critical IQ wide open on the smaller sensor.
I really really recommend the Sigma 30/1.4 Art for that camera, it is properly sharp and will give you a wide angle with shallow dof very desirable for car shots. It does suffer a bit from longitudinal CA's but that's pretty common until you start spending megabucks on lenses.