My bike seems to have developed a clacking (or 'clinking') sound. It seems to occur when I push hard on the left pedal and the harder I push the louder the clack or clink. I thought maybe the chain was clipping part of the metal guide but I looked at the drive train while pedaling and can't see anything coming in contact with anything else (plus it does always seem to be related to pushing on the left pedal although the sound just doesn't seem to be coming from the pedal). Other than the sound the bike is still moving smoothly.
Could it be the pedal or the crank? Would it make sense to try replacing the pedals?