Importance of ground wires near rear hatch

Thought I'd share some info with you. Awhile back I was working on installing a custom rear bumper, I pulled the rear plastic interior panels, then removed the spare tire mount to get some room around the filler neck. In the process I had to remove 2 small gauge ground wires that are on each side of where the interior tire carrier mounts. I finished what I was doing and forgot to hook them back up. I went to move the truck and you'll never guess what happened.

First, check engine light came on, truck had an erratic idle, 1500 down to about 300 rpm. Almost felt like there was water in the fuel. Scratched my head for awhile, started tracing my steps, found the ground wires and rehooked them. Started it back up and she was smooth as silk.

Not sure what those grounds go to BUT THERE IMPORTANT!!!

Truck is an 01 XJ Classic.

Same issue here, when I chopped the rear off, one ground wire was left loose. Stalled out, ran rough. Traced the ground with the FSM, but it's just a ground from a tie in point, not a specific trace. Did not research the circuit they are part of, just went with making sure they are hooked up. Thought is was a little strange, though.
01 XJ Sport, slightly modified

fuel pump ground?

Do those ground wires attach to the body or the bracket????
Because I just threw my bracket away!!!

they attach to the body but right next to the bracket