The engine makes a knocking sound that got worse until the motor froze. took to five auto shops including one specializing in Mazdas only. The engine also would burn oil and as the problem got worse more oil would be used. The problem only occurred during acceleration and shifting making it hard to pinpoint. No loss of power, no of brakes. Everything ran fine till the day it froze up running in the driveway fully oiled and plenty of gas. Car has been torn apart and rebuilt multiple times. Problem has never been fixed and we havent been asked for payment from any shops because problem still exist.