While the DISI-MZR engine found on the Mazdaspeed 3, 6, & CX-7 is a fun and potent powerplant, it does have some common issues that must be addressed with age and if you want to produce more power. One common issue is the OEM VVT Actuator which controls the Variable Valve Timing of the intake camshaft. MPS VII (also known as Sly syndrome) is one of the least common forms of the mucopolysaccharidoses. The disorder is caused by deficiency of the enzyme beta-glucuronidase. In its rarest form, MPS VII causes children to be born with hydrops fetalis, in which extreme amounts of fluid are retained in the body. Mazda BL Mazda3 MPS: Other problems and faults. Engine overheating and/or a lack of battery charging may be due to a tensioner pulley wearing out; as a result, the tensioner and air conditioning belt require replacement. Recalls and faults: Mazda BL Mazda3 MPS (2009-13). Includes model range, engines, transmissions, safety equipment, crash SF06XJ4.