On my C4 1993 I have a ticking that sounds like a valve, however it is not there when the engine is cold and when temp is normal operating it goes away after reaching 15 to 16 hundred RPM’s. I have listened with a stethoscope to the upper side valve covers and the lower side and heads, as well as the fuel injectors on both sides, with no out of the ordinary sounds. It doesn’t cause performance problems and the temps are all in the normal range. Oil pressure and temp is where it should be. The ticking is not as fast as a valve would be as I can count the ticks for the most part at idle around 2 to 3 per second.
I have been told everything from that this is normal, and that it is a fuel injector and a few other things, but to no avail as to what it could be. Any ideas?

is the car a auto or manual. i have seen a flywheel give that kind of sound in auto's. but to me it kinda sounds like it could be a rocker tick. not lifter tick...

I know this might sound alittle off - but that 2 to 3 tick per second @ idle sounds like the rate that a fan belt travels... Do you have a component on - say the fan belt train that might be ever so slightly bent (touching a bracket or block), etc....???

no it would be a different sound. my gto has had a upper tick since i bought it. it now has 89.000 miles on it and nearly 40 since the mods. i have not yet found what it is. but i have seen just about every lsx do it. now your's still has the old style rockers, and it might just be that one is giving you fits.