protouring "rake" causing issues with fuel tank utilization

What sending unit do you have in the car? If you are running an aftermarket sender, they are notorious for incorrect readings. If you have the OEM sender, look up Wolf & Sons & send it to them to have it rebuilt. If not, see if you can acquire one in the wanted section here & send it off. There have been multiple discussions as to the accuracy of the chinese built senders on this site.