No I already checked for remote mounted driver, that car don’t have that system.
Yes you are reading it right pnk/blk and blk.
Look at that diagram and look at all the voltage stops along the way and where ever there is a component there is a potential for a voltage drop starting at the fuse box feed to the fuse.
It only requires battery source voltage from the output of the fuse so if you confirm the 6.65 volts at the pump, change over to the ground wire side and run the test lead from battery positive to the fuel pump ground and if it reads 12.4 (or whatever source voltage is) then the ground is perfect but the problem is in the positive side circuit of the vehicle harness.
You can move on from there and test the voltage drop at the output of the inertia switch, relay, fuse and if you have 6.65 there, then the problem is in between that component and the pump connector.
Let me know if you don’t understand and I will break it down for you.
I mean lets make an example…
The battery for the available source for what it is of say 12.5 with the fuel pump energized (fuel pump prime, key on engine off) so we leave the battery with 12.5 and go to fuse f16 utilizing a protection of 20 amps(and still having 12.5) following that wire to the fuel pump relay and exiting (still having 12.5) then on to the s138 splice(still having 12.5) then passing through the crash safety feature inertia switch exiting with (6.65) and continuing to the pump connector (with only 6.65). In this example the inertia switch is causing the voltage drop because we should transfer the full 12.5 to the pump with the pump energized(fuel pump prime, key on engine off) but can’t because say the windshield leaks water into the cabin and down the A piller into the switch causing corrosion and a bad connection. (true story on an f series truck)