Fuel System Head Scratcher

So I put a new fuel regulator on and I'm still having the exact same problem. I really don't want to put this new pump on there if it isn't going to solve my issue. I really don't want to just throw parts at it if I don't need to.

 

Bit of an update, fuel pressure regulator was replaced, as was the fuel transfer pump and the primary filter housing base. I blew out all lines, and cleaned the TPS and the cam sensor. I'm starting to really think pickup tubes have gone bad in the tanks. Only problem is, I cannot check them as it appears they are welded into the tank. I'm going to put a brass ball valve in between the tank and fuel lines on both tanks and close off one tank at a time and drive it and see if it acts up. This way possibly figuring out which side has the bad pickup tube in it.

 

Anyone know what size ball valve I would get for these two lines based off this pic?