Small metal clicking noise when I push gas pedal

Is it just one click noise per push of the pedal or is it a repetitive clicking noise that gets faster as the engine speeds up? if its from the engine, it could be a warped valve making contact with the cylinder head. not a HUGE problem but causes less MPG and less power. to fix that, (assuming you know which valve is warped) youll need a lot of time, a lot of patience, a valve spring compressor (looks like a C clamp,) different socket wrench tools, possibly some screwdrivers, and maybe a couple more misc things. procedure: youd drain the oil, take off the valve cover, detach exhaust manifold from cyl head, remove the cylinder head, use the spring compressor to tighten the valve spring down to remove the old valve, then install the new one, put the head back on, reattach exhaust manifold, put the valve cover back on (might as well replace head and valve cover gaskets while you have the chance) then fill the oil back up. also if you had to remove anything above the valve cover to get to it, reinstall those as well.