95 civic fluttering engine?

Hello all. I have a 95 civic 1.5L SOHC that makes a metallic fluttering sound on slightly hard to hard accelration in practically every gear. More easily noticed in 5th gear when slowly climbing a shallow grade. Is this a valve problem? What should I do here? I recently replaced my timing belt and considered it a pain to do, but not difficult. Any thoughts on if I would be able to do this myself, and if so, what exactly? Many thanks in advance.

Regards,

Steve