I dropped the old fuel tank on my '70 Impala in 2024, and replaced it with a new stainless steel tank and new, correct-vehicle sending unit. Right away, I had an issue with the dash fuel gauge dancing around while I drove and braked, as if the sloshing of gas was registering with the float and affecting the dash gauge needle. I've lived with this for 2 years, but finally determined that the sender might've been defective. I ordered another one, dropped the tank and swapped out the sender, and am still having the same problem. My ground is good, the fuel hoses and return are connected properly. I'm confused. I've been told that I might have a bad resistor associated with the dash fuel gauge, but would this explain the slosh effect? A service rep at the local Chevy dealer said that maybe there should've been some type of baffle system to prevent this, but the techs where I bought the tank say there was never any such baffling system. Has anybody experienced anything like this?