I purchased this truck with that problem no pressure on gauge and ticking noise on lifters, I replaced the oil pump still no pressure, I install a mechanic oil pressure gauge still no pressure (I have the top part partially disassembled so the truck only runs for a few seconds) I toke it apart to check the rockers and they have to much play I think, so I'm planning in replacing the lifters but there is some other reason to no have oil pressure?
This is a 1995 f150 4.9 whit 220000 miles and manual transmission thanks in advance.

 

Did you inspect the pickup tube and screen?

Is the oil pump driveshaft hex end rounded off? It could also be rounded off on the top side that goes into the distributor.

 

I checked and clean pick up tube and screen, Driveshaft is good today I removed the oil filter and I started the truck for a few minutes and there it's almost no oil coming out from the oil filter hole

 

Previous owner put some kind of oil stabilizer and the oil was tick like honey, I change the oil and I notice there it was no oil in the oil filter at all, any chance the that tick oil clogged oil passages/lines?

 

The old oil should clear out of the passages if the new pump is working right. If I where you I would try to prime it with a drill and see if it bulids pressure the make a prime tool to use with a drill iv all ways just cut up a old dizzy and do it that way with a drill

 

Ok ill try that this truck has a new distributor but ill do that anyways to see if I can get some pressure

 

The sixes aren't very hurt by low or no oil, I wouldn't be surprised if it's been running this way a while

 

But whats the most common cause for that problem?

 

Usually it's just a worn out oil pump, which you've eliminated, or operator neglect (low/dirty oil, oil leaks, etc) which is a possibility with any used truck, but pretty unlikely

 

The guy who I bought it from owned the truck since 1999,and he gave me all the service records since then, he told me the noise and no oil pressure started after the last oil change

 

Sounds like a chunk of crap broke out of the oil pan and got sucked into the oil lines during the last change, not sure what else it could be