In hard acceleration fuel pres. drops to about 5lbs.new pump(twice)3/8"supply line,pressured tank to help siphon(inline 2000 pump)pinched off return (helped a little but not enough)new filter,this has been going on for some time and tuning is impossible.This is on a built 350 with 90lb. injectors running just under 14lbs. of press.when at idle and when return is restricted, press. rise a kills engine like it should.