acutally, that was ME who did all that... ATF is actually a pure detergent oil and will dissolve carbon build up and unclog the oiling passages.

the problem with the 1G and 2G lifters is that the oiling holes in the HLA's are so small, that over time the oil cokes up inside the holes and they get clogged. when they get clogged, they cant pump up and "Adjust" the "Lash" in the "Hydraulic" fashion in which they were designed for... if they dont pump up and aborb the Lash, they leave a gap, and when the cam followers move up and down on the Lobe, they tap. This tapping gets picked up by the knock sensor sometimes and creates "Phantom Knock" and will cause the ECU to pull timing and youll lose horsepower.

you can get HLA's for $7.42 each, theres a sticky in the parts section of DSMtalk.com. Make sure you get a new Cam cover seal and spark plug well seals including the half-circle cam plug. You might as well get the CAS O-ring too if you have a leak problem.

there is a way to change out the HLA's w/o removing the cams, it takes a couple big screwdrivers to pull this off.

there is a VFAQ on how to do this, it worked for me... took me a little over an hour to change all 16. the thing purred after that.

If you cant justify spending ~$150 for parts just yet, go ahead and do the AFT trick at every oil change, and run Castrol GTX... GTX seems to quiet down the noisy lifters for some reason. If you need help, i can tell you how to do the AFT trick.