One problem related to engine knocking noise has been reported for the 2004 Mazda MAZDA3. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Mazda MAZDA3 based on all problems reported for the 2004 MAZDA3.
No problems from car no warning light. Big bang then engine making very loud knocking noise. . . On interstate. . . Still cranks but needs motor. . . Read that lot of people have had same problems.