Is the fuel pressure from pump to fuel distributor good? you have an accumulator at the rear of the car if the diaphragm is leaking internally ie bypassing pressure you need to check that too, FUEL INJECTOR opening pressure is approx 4.3 to 4.6 or 3.7 with used injectors , get a fuel gauge to perform tests , you can also do a fuel supply test should pump out 1 liter of fuel in 20 seconds