Hello, I have an '01 Yukon 5.3 that recently started to give me problems. I recently replaced the knock sensors, spark plugs & wires, and fuel filter. After a test drive, thankfully in my driveway, it sputtered and died. Got the dreaded random misfire trouble code. Now it wont start at all, like it's not getting any fuel. (replaced fuel filter after this problem started btw). I can hear the pump prime when the key is turned on. I'm kinda leaning towards fuel injectors? My question is, if I try to test the pump pressure, is the fuel pressure release valve before or after the injectors?