Fuel pressure dropping while driving and under acceleration to zero at idle runs 4 lb electric Blue

Just an update. I shorten the supply line about 9 in so now it comes straight out of the sending unit down to the fuel pump. The only pull it has is up the sending unit from the bottom of the tank. It made some difference but still drops when you get above 2000 RPMs. My next thing I'm going to try is to put a valve on the return and see if by shutting it down I can keep the pressure up. If not, I'm going to put a sump in the bottom of the tank and feed the fuel pump straight from the sump.