<PAGE>

                                                                   Exhibit 10.40

                              AMENDMENT TO CONTRACT
                            DEALER GASOLINE AGREEMENT

                                                           (Branded Diesel Fuel)
                                                                 Facility: 82064
                                                       Customer Account: 0883355

THIS AMENDMENT, dated as of Sept. 2, 1999, amends the Contract Dealer Gasoline
Agreement ("Agreement") dated Sept. 2, 1999, between ARCO Products Company (a
division of Atlantic Richfield Company, incorporated in Delaware) ("ARCO") and
LLO-Gas, Inc. ("Buyer") with delivery premises at 64200 20th St., Palm Springs,
California 92258 ("Premises").

It is hereby agreed by and between the parties that effective on the date
written above or the Commencement Date of the Agreement, whichever is later, the
Agreement is hereby amended to provide that except as set forthbelow, any
references to "motor fuels comprising gasolines and gasoline-containing
materials bearing the ARCO trademark and other identifying symbols," "gasoline"
and "product" shall be construed to include such motor fuels comprising diesel
fuel and diesel fuel-containing materials bearing the ARCO trademark and other
identifying symbols ("ARCO branded diesel fuels and diesel fuel-containing
materials") as Buyer may purchase and receive from ARCO and ARCO may sell and
deliver to Buyer at the Premises during the term hereof.

It is understood and agreed by and between the parties that Temporary Voluntary
Allowances ("TVA's") are not applicable to diesel fuel or diesel fuel-containing
materials and, therefore, the terms and conditions relating to TVA's set forth
in the Prices provisions, Paragraph 5 of the Agreement, are not amended and
supplemented by this Amendment. It is further understood and agreed by and
between the parties that, except as herein specifically amended and
supplemented, all other terms and conditions of the Agreement, as previously
amended and supplemented, shall be and remain in full force and effect.

This Amendment automatically supercedes and terminates, as of the Effective Date
hereof, any and all other contracts, agreements or understandings between the
parties covering the sale and delivery of ARCO branded fuels and diesel
fuel-containing materials to Buyer at the Premises for resale therefrom.

BUYER ACKNOWLEDGES THAT BUYER HAS READ THIS AMENDMENT AND FULLY UNDERSTANDS ALL
OF THE TERMS, PROVISIONS AND CONDITIONS HEREOF.

This Amendment is not binding until executed by Buyer and by an authorized
officer or manager of ARCO.


IN WITNESS WHEREOF, the parties have executed this Amendment.


ARCO Products Company,                     Franchisee
a division of AtlanticRichfieldCompany


/s/ Connie Carroll             9/2/99      /s/ John Castellucci           9/2/99
-------------------------------------      -------------------------------------
                                 Date                                       Date


/s/ Hollie Johnson             9/2/99      /s/ Denise Newton              9/2/99
-------------------------------------      -------------------------------------
                                 Date                                       Date