Dual fuel tank issue

[dssranger]

I have a 1986 Ranger with dual factory tanks. The issue is the front tank. After I replaced the fuel injectors, I noticed the front fuel tank seemed to be buzzing louder than usual. I do not remember if it was doing this before I changed the FI's. But I decided to replace the fuel pump in it and the high pressure rail pump. It did not make any difference in the noise. The performance has not suffered, I still run off the rear tank. I have not disconnected the electrical harness from the tank to see if the pump is making the noise or if there is a problem with one of the lines going to the engine and returning. There is 6 lines that ultimately run from the selector valve for the tank selection. I am thinking maybe one going to the front tank has a air leak and is causing the return line to suck air causing it to sound like it is pumping continuously. Could the charcoal canister have anthing to do with it? Any suggestions would be appreciated.