Fuel Flutter??

[Wojo]

I have an autometer mechanical fuel pressure gauge mounted under the hood of my truck. when i first installed it it worked great for the first month or so. then all of a sudden it started fluttering nonstop like when your boost gauge flutters at high boost if not hooked up properly. my gauge does this nonstop no matter what you do UNLESS you unhook the fuel line from it and hook it back up. then it will read fine untill it bleads the air out of the system. i also have a #5 injector going out (still within specs) but i get a really bad cold start and when on a factory tune only when i rev it i can feel and hear it miss and it will blow a cloud of white smoke. when im on one of my regular tunes from innovative it will not do anything but have a rough cold start. truck still has plenty of power and still makes boost fine. also. if you stab it from a stop it lags really bad and when your on a tune (extreme street mostly) and you stab it from a stop it wont really go anywhere it will just dump a BUNCH of black smoke till the turbo spools up. is this normal?? if not what is my problem?? thanks guys

[Wojo]

i should also mention i replaced the ICP sensor tonight and it did not change a thing. ficm is fine and reads 48 volts and was just replaced last november. crank, cam, and map sensors are all new also.

[m-chan68]

You've just answered your own question. If cylinder #5 injector is weak under any circumstance (ie cold engine start-ups, misfiring under load etc.), it needs to be replaced PERIOD. To diagnose properly, you would need to leave the truck overnight and have someone with a Ford IDS scan tool connected to it and the power balance graph up and running, ready to view it when the engine is started cold. Once the engine is started, the FICM compensation mode would need to be disabled to view the weak cylinder(s)/injector(s) and replaced as necessary. Once this is done, a fuel pressure check would top off the repair. By the way, replacing the fuel pressure regulator with the updated "blue spring" style would hurt either, while you're at it (part number 3C3Z-9T517-AG).

[Wojo]

All that has been done besides the fuel pressure check because I have the gauge. Is there any reason
My gauge could be fluttering like that. Could I use a cheap oil pressure gauge az a fuel pressure gauge to see if my gauge is broken or what the deal is? Also do u think that the bad injector I have would be the cause of my white smoke at cold startup or could that be a different issue?