The pumps are difficult and expensive to upgrade, and replacing them is often out of the question for station owners who are still just scraping by.
Many of the same pumps can only count up to $99.99 for the total, keeping owners of some SUVs, vans, trucks and tractor-trailers from filling up all the way. As many as 8,500 of the nation's 170,000 service stations have old-style meters that need to be fixed -- about 17,000 individual pumps, said Bob Renkes, the executive vice president of the Petroleum Equipment Institute of Tulsa, Okla.
"The new ones run between $10,000 and $15,000 apiece," said Chip Colville, who owns a gas station in town. "It's an expense that's not worth it."
Mechanical meters can be retrofitted with higher numbers when pump prices climb another dollar. The last time that happened was in late 2005, when gas went over $3 a gallon, and owners of the older pumps installed kits that went to $3.999.
This time, owners of the old pumps will need to install another kit that can handle prices up to $4.999, and possibly higher. Experts say those changes could cost as much as $650 per pump.
It costs less to change the meter to raise the maximum price from $2.99 to $3.99 a gallon, but that option raises the risk of a breakdown, said Pete Turner, the chief operating officer for APS Petroleum Equipment Inc. of Anniston, Ala.
Nationally, the average price for a gallon of gasoline rose past $3.70 on Sunday, while diesel was selling for an average of $4.33 a gallon, according to AAA and the Oil Price Information Service.