Re: knocking or ticking noise
Is the engine running rough as well? A real misfire at least would let it run rougher at least in idle. If the lash adjuster gets real bad, it could even cause the rocker arm to fall of and then for sure you will have a real misfire and a rough running engine. But also a dropped valve seat could cause the rockerarm to fall of. I would remove the left cylinder head cover and have a look if the rocker arms from cylinder #1 are in place. You can then also feel the rockers for any play, good valve lash adjusters should keep the rockers without any play.