Last week's red hot auto sales under the government's "Cash for Clunkers" program are cooling off.

One industry analysis released Tuesday predicted a steady decline in clunker-related sales, despite the addition of two-billion-dollars to the program by Congress and the Obama administration.

Edmunds.com Senior Analyst Michelle Krebs says interest is dying down as dealer inventories tighten. Auto dealers are also seeing a slowdown in showroom traffic from the frantic pace of a week ago.

According to government and industry figures, sales during the peak period topped 250-thousand and rebates exceeded one-billion-dollars.

Under the Clunkers program, customers can receive rebates of up to 45-hundred-dollars by trading-in older cars for more fuel efficient new ones.

Dealers say buyers are trading in mostly sport utilities, pickups and other American-made vehicles for fuel sipping foreign-made passenger cars.

Automakers credited clunker trade-ins for boosting July sales in a year in which they've had to contend with a devastating drop in business.

On a related note, the Obama administration is considering modifying the program.

"The Wall Street Journal" says the change would allow Americans wishing to trade in older gas guzzlers to receive a voucher or rain check good toward a future purchase.

The original program has been so successful that many dealers report they have few if any qualifying fuel sipping vehicles left to sell.

Click here for more information about the "Cash for Clunkers" program.