Just to give my .2 cents. Me and buzz been talkin online. But wanted to state what i think it is.
If afrs seem to not be stable, Or if all of a sudden you start to knock and you have not changed a thing, its 99% chance its a clog. Clogs can cause your system to losse psi, there for losse volume, can change your nozzle pattern, and cause your pump to act, pulse differently ect. a clog most likley is in your nozzle, HOW EVER i have had a check valve clog as well. They are EASY to take apart all you need is some c clip plyers. Theres a small c clip in the front of the valve, Take your plyers and go fishing for it. Theres a spring and plunger, take these out. When i did mine there was a little piece of dirt, that was stuck between the spring and plunger. There for, the plunger would get stuck shut or open or anywhere inbetween. Once clean and fixed, acted normal again. Nozzles also can be takin apart, Most of the time theres dirt around the filter, causing it to be blocked and losse psi. Clean filter take apart the brass jet andthe little ball thingy, and clean well.
IF you have a soild system no knock and good afrs, than one day you knock and afrs are all out of wack. I bet you have some dirt in your system
Buzz than told me that he JB welded his tip to his 90 degree angle, Because of boost leakin? PLEASE dont do this!!! you can not clean your nozzle if you have a clog. And you do not need to JB WELD the nozzle to the tip. If it leaks meth or boost, use Tape thread seal or liquid to seal it, That way you can get it apart
