e30 fuel pump problems

:flash: my 1989 e30 316i is eating fuel pumps. after a week she devlops a lack of power as if fuel starvation with it becoming progressivley worse until popping starts from the airbox and soon after she starts to backfire.it has motronic fuel injection and have gone through the whole engine bar removing the block. Fuel filters have been replaced, new leads and plugs, inlet manifold, was hooked up to a diagnostic computer and showed no faults. please help

You did not mention if you checked the other fuel pump, (one in the tank and one under the car) but your year model may not have one.
How about the fuel pressure regulator?
How is the fuel line?