Is a capacitor to reduce noise on the radio and help the instrument voltage regulator last longer.
The typical sender will have a resistance range some are 10 to 80 ohms. Part of the problem is the float arm is way too short, the other is the aftermarket senders are not designed for the shape of the tank.
As Lord sparky pointed out there are a ton of posts about the issue.
Your best bet is if you have your original and it is not a rust bucket send it out to be rebuilt.
There are devices called meter match that can help.
