2000 malibu no oil to rockers

[p8ntman777]

I have a 2000 malibu ls 3.1L 101k i bought that would not start. The ecm had been changed and not flashed. befor i took it over to the dealer to be flashed i had my mechanic change the upper and lower intake and gasket because for some reason it had been cracked and welded around some of the ports and a threaded ear on the lower was broke off. after repair i had the ecm flashed and car started and ran fine except for there was a sound like a lifter tic. mechanic says its from sitting and needs to run for a while and it might pump back up. long story short i pulled off the front valve cover and put water lines back on and started it up and only one pushrod had a small oil flow. the noise does get alot quiter after several minutes of running, only run about a minute with valve cover off.
Any ideas what would cause this? Could it be from intake repair?
thanks in advance

[maxwedge]

I'd start by checking the oil pressure with an external gage.

[p8ntman777]

thanks for the reply, sorry it took me so long. oil pres is 35-40 psi at the plug next to the filter.

[maxwedge]

Let it run a little longer if no pressure to the rockers there is an internal problem, 3.1's that ran for an extended period of time with a coolant intermix can spin a cam bearing causing this issue.