My Mechanic replaced the entire fuel pump assembly to correct pressure isses/intermitent non-operation. My fuel level guge doen't work at this time/doesn't register at all, before the assembly was replaced it worked. My mechanic said it is probably a bad gauge, he is going to replace it again. The rest of the gauges work fine, could the gauge level in the fuel pump be faulty, or is it just a simple fuse?