Bad injector and 5th gear noise

[DataXUnknown]

I have 2 problems I need to get sorted out. So i think I have a bad injector, but I don't know which one. I searched but didn't find anything on how to find which one is bad and such. I have the whole subie sound every once in a while. It comes and goes it's wierd.

I know I need to change the fuel pump (running SR, with stock fuel pump from KA24E), I don't think that is the problem, but it might be as well.

Ok the 2nd thing is, when I put it into 5th gear, a lot of the time I will have a loud not really a grinding sound but more of a rumbleing sound. It's either in the driveshaft or the diff. I know my diff is leaking a lot, and it's welded, so I'm thinking it's the diff, but why only in 5th gear? And I can make the sound go away usually by taking it out of 5th and putting it in a wierd way.

Any help on this?

[superdaveosbourne]

For your first problem it could be something as simple and stupid as athe connection to your ECU. I was having the same subie sound and 1 dead cylinder in my GTR, turned out that my harness had almost completely backed off the ECU and was intermittently losing cylinder 1. Just tightened it back up and has been flawless ever since. When the problem happens, try unplgging your coils 1 by 1 to find out which cylinder it is. If you unplug one and the motor doesn't stutter any more than it was, you found the cylinder that isn't firing. Could also be wiring harness, injector like you think, or coil pack. Check the harness for conductivity to rule it out or try a different harness.

As for the second one, you're on your own.

[krisdeezy]

for the bad fuel injector you can pull one sparkplug off at a time and see which one drops idle. the one that does not drop idle should be the one with the bad fuel injector.