Eric34

I have a 2007 Silverado 6.0 vortec max (135000 miles) with a collapses #7 lifter. I am trying to do an AFM delete without changing the cam. I changed the 2 #7 lifters with AFM lifters, reprogramed the ECM and blocked the oil passage with a new non AFM Valley cover. I am not sure why the new lifters are activating without oil pressure from the VLOM. I don’t want to change the cam so I need to reinstall AFM lifters. Could it be that oil pressure is building up from the AFM lifter since the passage to the VLOM is blocked? Thanks Eric