For lovers of Tab it is the latest attempt to take away their beloved soda, a steady threat since Coca-Cola introduced Diet Coke in 1982.

“We’ve been through this before,” said Calvin Boyd, 51, a Tab drinker for four decades who works in the cargo department at Charlotte Douglas International Airport in North Carolina. “We know what to do.”

Some of them have signed a petition they plan to deliver to Coca-Cola’s Atlanta headquarters. Consumers are calling Coca-Cola regularly to complain. And they are demanding that grocery stores put Tab back on shelves. (A fan group is collecting comments on Facebook.)

Mr. Boyd said a friend of his approached the manager of a Publix supermarket in Charlotte about restocking the shelves. The manager offered to secure a shipment from a Publix in Florida.