stated above you can test most of it under the hood. Get 2 pairs of vise grips and something to put between them and the fuel hose so you don't damage the hose with groove marks. Put your fuel gauge on between the fuel filter and the fuel line on the engine. Do a control test and pressurize the fuel system and turn the car off and note how fast it drops. Now with the fuel system pressurized again clamp the return line and clamp the sending line between the gauge and fuel filter. You now have a closed off loop with your fuel gauge, fuel rail, fpr and fd. You can check the vacuum lines that go to the fpr and fd just to make sure they're dry while you note to see how long the fuel pressure holds. It should hold for a real long time. If it still drops just like the control it's bleeding into your engine through a fuel injector or an o ring. If it holds you can take one vise grip off at a time and that will tell you where your fuel is going. Take the vise grip off that's in between the fuel filter and gauge If the pressure drops the fuel is going back through the check valve or the little hose that connects the fuel pump to the hard line. If you take the vise grip off the return line first and the fuel pressure drops It's your fpr. Do both before you take the fuel pump out. If its the check valve I think you have to replace the whole pump. It's easy but you gotta be real cautious about fire and static electricity. Good luck
