5.3. #4 lifter cycles twice and then stops. Let it sit, cycles twice. Rocker is not loose. Installed vlom mod didn't cure it. Any ideas?

That hurts, but makes sense. Thank you for the response, your videos and products.

Thanks for posting, sounds like you have a bad plastic lifter guide. When this happens the lifter will rotate in the bore because the guide no longer does it's job. It tends to rotate a 180deg due to having a roller. This in turn makes the oil port that normally doesn't have pressure in V8 mode, face the main oil galley when it shouldn't. This pressurizes the AFM side of the lifter and thus collapses it. That is why shortly after you started it up, it collapses. It is receiving engine oil pressure shortly after startup. The end result of this is a bad deal. It wipes out the roller on the lifter and thus damages the cam lobe. Now is the time to do a full delete. You will need a non AFM camshaft, the non AFM plastic guides, the non AFM valley plate, and non-afm lifters. Of course don't forget. If you have not done a tune to turn off the AFM yet, be sure to do so. Options for doing the tune. You can use LT1swap.com if the system is going to be a stock non AFM system. Otherwise you will need a custom tuner if you plan to do any kind of custom camshaft grind. Be sure to avoid something like the range disabler device. They are not a actual tune and will make the vehicle enter limp home mode when a full delete is done.