1994 300ZX NA Lifter Tick, please read

[gearzablade]

94 300ZX NA

Just got the engine rebuilt and assembled it together. Only thing I didn't replace was the pump and injector, blah blah. Tested and looked through carefully.
So at idle, the car is fine, rev up fine at idle. But as soon we pull out to the street, sometimes, lifter would tick. On highway however, the lifter would definitely starts ticking. So basically, only
on hardpulls or a constant drive would make it tick. BUT, once it starts ticking, if you leave it in one place and let it idle, the ticker would QUIET down and stop making the noise. And once I drive it out on the street/highway again, it comes back, let it idle, gone. If I turn off the car WITH the lifter tick going, it takes longer for it to quiet down. It faster to let it idle and make it quiet down itself. Technically, it doesn't quiet down, it literally just stops. The noise is coming right below the oil cap, and I'm 100% sure it is the lifter. Confirmed by the HoustonZ guys also. Another, I believe one of my injector is stuck open or seal is messed up, (brand new seals of course) and is leaking fuel into the oil. Not sure if it related but throwing it out there.

I have tried 5w-30, 10w-30, and 10w-40 to see if it would help. 10w-40 seemed to help the most. Synthetic blend, 4 quarts, I understand it takes about somewhere in 3.
Replaced the oil pressure sensor and saw that pressure is fine.

Ideas?