[Tech II]

What was replaced, besides the chain? Cam sprockets? Crank sprocket? New tensioner shoe? New tensioner? You said plastic guides were ok.....

Was the new tensioner fully extended? Was the engine properly timed? Correct oil filter used?

I don't like the idea that you "cleaned" the oil pump......that pump has to be timed to the balancer shafts......there is actually a little chain coming off that pump, and if you took that apart, there is a bolt to the drive sprocket that should be replaced when removed....never mess with those pumps, unless you have proof the pump is at fault.....this is checked by removing a plug(in the lower block, rear, passenger side) in the oil galley right off the pump, and attaching a mechanical gauge there....

Have you checked the oil pressure in the engine? In the valley on top of the engine on the driver's side, is the oil pressure sender/sensor......attach a mechanical gauge to get pressures, on start up and when the engine starts to make noise.....