leaking oil out the back of my engine on the passanger side. im sure it is not the valve cover gasket as i just changed it.
i believe it is the oil sending unit as it only leaks when running and because of where the oil is dripping down from.
could anyone verify this for me please.

edit/ 2002 blazer 4.3L

 

Could very well be the oil pressure sending unit. The most common source of oil leaks from up high on the 4.3 is from the lower intake manifold gasket.

 

Well the sending unit had oil all around it and it seems to be where the drip originates from. I am going to grab one now with a oil sending unit socket as well.
Also I had to pull the distributor to get to the oil sending unit. When I did there was a circular gasket of some kind that just literally crumbled away from the top of the shaft of the distributor. Could someone tell me what that was?