I have had two occurrences of screws from the butterfly valves on the vtcs system from the intake of my 2003 Mazda Protege 5 coming loose and being sucked into the combustion chamber of the vehicle. Each instance has caused the piston to knock the screw into the spark plug, thereby causing failure of a spark plug, which causes the engine to misfire to the point where it is undrivable, thereby leaving me stranded on the side of the road. The first incident was misdiagnosed (spark plug replaced). The second was diagnosed correctly and the intake manifold assembly was replaced. This is a widespread problem with the 2.0L fs-ze Mazda engine. Many other owners have had the problem. For more information to demonstrate the prevalence of the problem, please visit www.msprotege.com and search using the keywords "vcts" and "screw". you will see many threads where people are discussing this problem.

- Clinton, MS, USA