3.0 engine noise

[stingray]

hey guys, i have a 99 ranger with 3.0 flex fuel,the problem that i'm having is the noise coming from engine,it sounds like lifter noise but i have removed all of the lifters,rocker arms,pushrods,everything looks good.the engine has 147,000 on it.i can hear the noise through the oil pan,the pass. side valve cover even through the right side exhaust manifold. all haeat shields have been checked,nothing there,removed belt,started truck,noise still there.i removed valve covers and loosened rocker arms one at a time to see if noise was worse or better,still the same.all lifters seem to be oiling good.has there been any problems with the rocker arms and push rods on these engines? i've had people tell me that it's a lifter but it sure sounds like a wrist pin or excessive piston slap or a broken skirt to me. i know that the 4.0 had rocker arm and push rod problems,just wondering if these engines had the same. any answers would be greatly appreciated,hate to replace motor but i like the truck so i guess i will if i have to. thanks.