I think my car has what you guys call piston slap but not very sure because the noise is heard when the car is warm and it only happens at about 2300 rpms. i went to my mechanic and when he was going through each cylinder he deactivated one of them by pulling something off and the noise went away. When he put it back the noise came back. What are the causes of this whole piston slap? Is it fixable and how much would it cost? Please help!!