well im been having this tap sound for a while i know for a fact is not a rod knock some guys said is valve train noise, well yesterday while warming the car the sound comes & goes open the hood i disconnected #3 injector the sound whent away but of course the miss is there !!! i replace lifters,new timming chain, chain front cover last summer, 100 lb valves springs just refresh my heads but the noise always been there. can it be a wrist pin? or worn rocker arms the car runs strong never had a ploblem, why does the noise goes away when disconect that cylinder? 
