Gas prices may be near bottom
Price at the pump continues to decline, according to AAA survey, but analysts say gas is near its low.
NEW YORK (CNNMoney.com) -- Gas prices fell 1.9 cents Thursday to a national average of $1.664 a gallon, according to a nationwide survey of gas station credit card swipes.
Gas prices have fallen for 85 consecutive days, according to motorist group AAA.
Prices are now $2.45 below the record-high average of $4.114 a gallon reached on July 17.
Gas has been selling at the lowest average price since February 2004, according to AAA data, and has fallen below $2 a gallon, on average, in all but three states: Alaska ($2.717), Hawaii ($2.511) and New York ($2.011).
Gas was cheapest on average in Missouri, at $1.45 a gallon.
The price of gasoline has fallen along with the price of crude oil, gas's main ingredient. Crude has fallen more than $100 a barrel since July as investors worried that the U.S. economy was consuming less fuel.
Touching bottom?: However gas prices may be starting to reach bottom, according to J. Scott Susich, senior partner at PumpPredictor.com, a gas price alert service.
"I think we're starting to flatten out," said Susich. "Crude oil seems to have found some stability."
The price of crude oil has been steadily rising since last Friday after touching a four-year low. This has thinned out the profit margins of many gas stations, according to Susich.
"The margins have now started to narrow up to the point where there's not much more [gas stations] can lower the price," he said.
Margins are tightest in cities with large working-class populations, such as Kansas City and Philadelphia, and those areas may be the first places to see prices level out or even tick upward again, said Susich.
Gas prices had fallen 0.3 cents in Kansas City to an average of $1.338 a gallon, according to GasBuddy.com, a company that lets users post prices at local gas stations around the country. Prices had fallen by 2.1 cents to an average of $1.774 a gallon in Philadelphia, according to GasBuddy data.
Demand for gasoline is still falling, however, and that's unlikely to change unless the economy turns around, said Susich.
Diesel: The price of diesel fuel, which is used in most trucks and commercial vehicles, also continued to slide.
The price of diesel dropped 2.3 cents Thursday to a national average of $2.594 a gallon, according to the AAA survey.
Diesel prices have fallen more than $2 a gallon since hitting a record high of $4.845 on July 17.
Ethanol: As falling demand pulled down gasoline and diesel prices, the price of E85, an 85% ethanol blend made primarily from corn, rose 0.1 cent to $1.510 a gallon on average, according to AAA.
E85 can be used in place of regular gas in specially configured "flex-fuel" vehicles, but it is not readily available in some states.
The AAA figures are state-wide averages based on credit card swipes at up to 100,000 service stations across the nation. Individual drivers may see lower fuel prices in different areas of each state. 
