It may be worthwhile to repeat your test using an analog multimeter instead of a digital- it may mimic the operation of the gauge better and not be so jumpy?
Both work by comparison using a very small current from a dry cell battery. I would like to test at least once more. I'll see what analog ohmeters I have with a scale in a useful range.
I'd 'just' swap out the sending unit on the engine except its in there really tight. :(
It's not the original. The original sprang a pinhole leak on the way to work in N Jersey. This is a NAPA replacement.
I do have a new replacement from BRE that is supposed to be 'correct'. At least in terms of matching the gage. I know its not correct in appearance. Not that it matters to me, jsut a heads up for those whom that is important.