Welcome to the world of repro sending units. And no you are not alone. The problem is so rampant that a company called Tanks Inc. makes a device called meter match. I believe Dakota digital makes one as well. I have yet to find a S/U that reads correctly regardless of the make/model of car or brand of sending unit. I am sure we have put in well over 100 various tanks and sending units in the last 20 years.