One problem related to emission control has been reported for the 2003 Mazda Protege 5. The most recently reported issues are listed below.
While driving normally to my home after work the car stalled at a stop light. )when restarted there was a loud clanking/hammering noise from the engine for about 15 seconds then the sound went away, the cell lit up and the engine started shaking. When checked for codes a misfire on cylinder -4 was found. (the spark plug on cylinder 4 had been smashed flat by a foreign object that caused the hammering noise, nothing was found inside the cylinder , using a magnet. The spark plug was replaced and the car worked as normal. Upon investigation on the internet I found recall 3005c for the vehicle that describes my problem and if not fixed can cause engine failure. When contacting Mazda customer assistance they said my VIN was not in range for this recall and that I would have to pay for any repairs because my car has 61000 miles and even though the emissions warranty is still active, the regular warranty is over.