HOUSTON (AP) - Texas motorists faced higher retail gasoline prices for a third week in a row.

The weekly Triple-A Texas gas price survey found regular-grade gas prices rose an average of four cents to two dollars 15 cents per gallon. The national pump price average rose five cents to two dollars 30 cents per gallon.

The most expensive gas was found in Amarillo, where regular grade rose an average of four cents to two dollars 26 cents per gallon. The cheapest gas was in Corpus Christi and San Antonio, where it averaged two dollars eight cents per gallon. That was a six-cent increase in Corpus Christi and a four-cent increase in San Antonio.

Auto club spokeswoman Rose Rougeau says the higher prices result from recent increases in crude oil prices, which topped 60 dollars per barrel this week. She also says U-S refineries are nearing their annual switch to cleaner-burning summer-grade fuels, which result in higher prices at Texas pumps.

These are average per-gallon prices of regular, self-serve gasoline in Texas metro areas and the change from last week, according to today's Triple-A Texas Weekend Gas Watch:

Austin-San Marcos -- $2.146, up 4.4 cents
Amarillo -- $2.261, up 4.4 cents
Beaumont -- $2.123, up 4.5 cents
Corpus Christi -- $2.084, up 5.6 cents
Dallas -- $2.161, up 4.6 cents
El Paso -- $2.184, up 4.8 cents
Fort Worth -- $2.157, up 4.7 cents
Galveston-Texas City -- $2.132, up 2.9 cents
Houston -- $2.129, up 4.5 cents
San Antonio -- $2.085, up 3.6 cents
Texarkana (Texas only) -- $2.173, up 3.4 cents

(Copyright 2007 by The Associated Press. All Rights Reserved.)

AP-NY-02-23-07 0810EST