Amendment No. 1 to Master Supply Contract for Resale of Oils and Greases between ExxonMobil Oil Corporation and Petro Stopping Centers, L.P.

Exhibit 10.38

AMENDMENT NO. 1

TO

MASTER SUPPLY CONTRACT

FOR

RESALE OF OILS AND GREASES

This AMENDMENT NO. 1 TO MASTER SUPPLY CONTRACT FOR RESALE OF OILS AND GREASES (this “Amendment No 1”) is made as of July 1, 2005 (the “Effective Date of Amendment No 1”), between ExxonMobil Oil Corporation (formerly known as Mobil Oil Corporation) (“Seller”) with offices at 3225 Gallows Road, Fairfax, VA 22037, and PETRO STOPPING CENTERS, L.P. (“Buyer”), with offices at 6080 Surety Drive, El Paso, TX 79905. (Seller and Buyer are sometimes referred to herein individually as a “Party” and collectively as the “Parties.”)

WHEREAS, Seller and Buyer have entered into that certain Master Supply Contract for Resale of Oils and Greases (the “Supply Contract”) dated as of July 23, 1999; and

WHEREAS, Seller and Buyer wish to amend certain terms, conditions, and provisions of the Supply Contract for the mutual benefit of the Parties;

NOW THEREFORE, the Parties agree as follows:

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(ii) Buyer agrees to purchase, or to use its commercially reasonable efforts to cause to be purchased at the Franchisee-Operated Truckstops, for the Truckstop Locations, the Minimum Purchase Gallons of Seller’s lubricants set forth in the table below for each remaining calendar year of the Initial Term, as adjusted from time to time pursuant to paragraphs (b), (c) and (d) below. The historical gallons requirements for the years 1999 through 2004 are shown for convenient reference. In the event that the Supply Contract is not extended into the Extended Term, the Minimum Purchase Gallons for the year 2009 shall be prorated, based on the actual number of days of Initial Term remaining in calendar year 2009. The Parties understand and agree that the Minimum Purchase Gallons for years after 2005 set forth below are based on an annual growth rate of one percent (1%) from the 2005 amount:

Minimum Purchase Gallons from PETRO Corp

Stores and PETRO Franchisee Stores

(iii) In the event that the Supply Contract is extended into the Extended Term, then (I) the Minimum Purchase Gallons for calendar year 2009 shall be 2,163,000, as indicated in the chart above (or as adjusted pursuant to paragraphs (b), (c) and/or (d) below), (II) the Minimum Purchase Gallons for calendar years 2010 through 2014 shall equal the Minimum Purchase Gallons for

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calendar year 2009, and (III) the Minimum Purchase Gallons for the year 2014 shall be prorated, based on the actual number of days of Initial Term remaining in calendar year 2014.

(iv) Buyer understands and agrees that except as set forth in the paragraph immediately below, and except for adjustments made pursuant to paragraphs (b), (c), and/or (d) below, the Minimum Purchase Gallons set forth in the table above, and in paragraph (iii) immediately above, are firm figures, and that if the total aggregate gallons required for the five (5) year period 2005 through 2009, (as these amounts may be adjusted in accordance with the terms and conditions of this Amendment No 1) are not purchased by Buyer and Buyer’s Franchisee-Operated Truckstops, then Buyer shall pay Seller, promptly after the end of such period, One Dollar ($1.00) for each gallon that such actual purchases for that period fall short of the aggregate required gallons for that period. In the event that the Supply Contract is extended into the Extended Term, and Buyer and the Franchisee-Operated Truckstops do not purchase the total aggregate gallons required for the five (5) year period of the Extended Term, then Buyer shall pay Seller, promptly after the end of such period, One Dollar ($1.00) for each gallon that Buyer’s actual purchases for that period fall short of the aggregate required gallons for that period.

(v) In the event that the price of bulk Delvac 1300 Engine Oil to Buyer from Seller for any consecutive sixty (60) day period in a calendar year is equal to or greater than the higher of (i) the price of Shell Rotella T plus ten (10) cents a gallon or (ii) the price of Chevron Delo plus ten (10) cents a gallon, then (i) the Minimum Purchase Gallons for that calendar year shall be reduced by one percent (1%), (ii) the remaining calendar years of the Initial Term shall be recalculated from such reduced base using a one percent (1%) growth rate, and (iii) if the Supply Contract is extended into the Extended Term, the remaining calendar years of the Extended Term shall also be recalculated accordingly, using a one percent (1%) growth rate.

(vi) In addition to the purchase requirements set forth above, Buyer shall purchase from Seller, in aggregate for Buyer-Operated Truckstops, ninety-five percent (95%) of all of its requirements of synthetic lubricants and ninety-five percent (95%) of all of its requirements of all lubricants other than diesel engine oils.

(vii) For purposes of this Supply Contract, 8 pounds of grease equals 1 gallon of conventional oil and 1 gallon of synthetic oil

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equals 4 gallons of conventional oil. As used in this Supply Contract, the terms “Seller’s product” and “Seller’s lubricants” are used interchangeably.

Permanent Adjustment: Upon the occurrence of any of the following events, the Minimum Purchase Gallons shall be permanently reduced by the Effected Volume (as defined below): (i) if a decision is made by the Board of Directors of Petro Stopping Centers, L.P. to divest a Truckstop Location; (ii) as a result of an action of eminent domain, a Truckstop Location’s operations must be permanently shut down; or (iii) ExxonMobil discontinues, without replacing with a comparable product, any Product listed on Exhibit 2 (a “Product Discontinuation”).

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Temporary Adjustment: Upon the occurrence of any of the following events, the Minimum Purchase Gallons shall be temporarily reduced by the Effected Volume: (i) ExxonMobil’s inability to supply product at a Truckstop location for a period greater than 30 days; or (ii) because of a Force Majeure Condition (as defined in Section 10 below), Petro is unable to operate the Truckstop facility for a period of greater than twenty-four (24) hours. Petro shall advise ExxonMobil of any of said outages in a timely fashion in order to establish a Temporary Adjustment.

Effected Volume: The “Effected Volume” will be calculated as 30,000 gallons for Buyer-Operated Truckstops and 20,000 gallons for Franchise-Operated Truckstops (plus the cumulative volume growth using the one percent (1%) growth factor applied pursuant to Section 1(a) up to the date of the Temporary or Permanent Adjustment) for each Truckstop Location affected by one or more of the above-described events, prorated over the period of time that the event is in effect for that Truckstop Location, except that if the only such event for a Truckstop Location is a Product Discontinuation, then the Effected Volume will equal the average annual volume of that product that Buyer purchased from Seller during the three (3) years preceding such Product Discontinuation, prorated over the period of time that the Product is Discontinued.

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1. Buyer may participate in no more than two (2) thirty-day competitive consumer promotions, one in the Spring, and one in the Fall, for so long as monthly sales of ExxonMobil lubricants at all Buyer-Operated Truckstops never fall below the larger of (i) fifty-nine percent (59%) of monthly total sales of all lubricants at all Buyer-Operated Truckstops, or (ii) the 3-month rolling average of Buyer’s purchases from ExxonMobil of ExxonMobil Lubricants calculated for the same month of the previous year, plus 15,200 gallons.

2. If Buyer does not achieve the sales specified in paragraph (1) immediately above, Buyer may participate in no more than one (1) thirty-day competitive consumer promotion, either in the Spring or the Fall, for so long as monthly sales of ExxonMobil lubricants at all Buyer-Operated Truckstops never fall below the larger of (i) fifty-four percent (54%) of monthly total sales of all lubricants at all Buyer-Operated Truckstops, or (ii) the 3-month rolling average of Buyer’s purchases from ExxonMobil of ExxonMobil Lubricants calculated for the same month of the previous year, plus 4,400 gallons.

3. If at any time Buyer does not achieve the sales targets specified in either of paragraphs (1) or (2) above, then Buyer must cease participation in any competitive consumer promotional activity. Buyer may resume participation in competitive consumer promotional activity only when sales targets specified in either of said paragraphs (1) or (2) are met for six (6) consecutive months.

4. Promptly after the end of each calendar month, Buyer shall submit to Seller in writing a report showing Buyer’s monthly sales of ExxonMobil lubricants at all Buyer-Operated Truckstops and Buyer’s total monthly sales of all lubricants at all Buyer-Operated Truckstops.

1. If furnished by Seller, display two (2) “We Proudly Feature” signs in plain sight, where customers are most likely to see them;

2. Install an internally illuminated Delvac sign (4’x6’), which shall be provided by Seller;

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3. Display a Mobil Delvac Bay Banner, which shall be provided by Seller, inside the garage;

4. If furnished by Seller, prominently display Mobil Delvac counter mats, counter top displays, and other identifying items.

5. Display no permanent competitive signage on the premises;

6. Give preference to ExxonMobil in the display of all temporary signage, including but not limited to, banners, mats and snaplock inserts if furnished by Seller;

7. If furnished by Seller, display Seller’s promotions; and

8. Fifty percent (50%) of shelf space dedicated to engine lubricants must be used for the display of Exxon and Mobil brand engine lubricants.

1. Buyer shall maintain and preserve, in accordance with generally accepted accounting practices, accurate documentation and data related to lubricant purchases.

2. At all reasonable times, Buyer shall permit employees and agents of Seller to have access to Buyer’s offices and work locations to examine, reproduce and retain copies of such documentation and data and to interview Buyer and its personnel in connection therewith, as necessary for Seller to verify and monitor the accuracy and sufficiency of documentation, data, and records related to the Supply Contract and this Amendment No 1, including but not limited to the competitive volume information provided by Buyer to Seller.

3. The provisions of this section 2(g) shall be applicable during the term of the Agreement and for a period of three (3) years thereafter. If errors or deficiencies are identified by an audit or otherwise, Buyer shall take prompt corrective action and promptly advise Seller thereof.

3. Term. The term of this Supply Contract is for an initial term of ten (10) years, beginning on the Effective Date and ending on the tenth anniversary of the

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Effective Date (the “Initial Term”). In addition, Seller may, at Seller’s option, extend the term of this Supply Contract for an additional period of five (5) years (the “Extended Term”). Upon the exercise of this option, said extension shall be for the same consideration and under the same terms and conditions as herein provided, and no new agreement need be entered into. Seller may exercise this option with or without exercising its option to extend that certain PMPA Motor Fuels Franchise Agreement of even date with the Supply Contract. Seller may exercise its right to extend the term of this Supply Contract by giving Buyer written notice of such election not less than 180 days prior to the expiration of the Initial Term. In the event Seller elects to so extend the term of this Supply Contract, Buyer shall have the right to cancel this Supply Contract at the end of the Initial Term by giving Seller written notice of such election not less than sixty (60) days prior to expiration of the Initial Term and paying to Seller on the last day of the Initial Term a termination fee equal to the present value of the anticipated income stream from One Dollar ($1.00) times the aggregate required gallons for the period of the Extended Term, discounted at 12%, based on a five (5) year stream received in arrears, as calculated in accordance with Paragraph 1(a)(iii). Buyer’s obligation to pay this termination fee is independent of any other obligation to pay for any shortfalls, and one shall not be carried over to or netted against the other.

5. Buyer shall pay to Seller in addition to the prices provided for herein any foreign or domestic duty, tax, sales tax, excise tax, fee or other charge, whether or not of the same class or kind, now in effect or hereafter imposed or assessed (but exclusive of taxes based on net income) which Seller or Seller’s supplier, direct or indirect, may be required by any municipal, state, federal or foreign government law, rule, regulation or order, to collect or pay with respect to the production, manufacture, sale, transportation, storage, delivery, or use of Product sold hereunder, and which is not otherwise given effect in Seller’s applicable prices.

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(a) If Buyer is in default under this Supply Contract, or under any other agreement between the Parties: (i) Seller may suspend deliveries (to the Truckstop Location in default) during the default; (ii) Seller shall provide notice of default to Buyer and Buyer shall have thirty (30) days to cure such default; thereafter, if the default continues, Seller may terminate this Supply Contract with respect to the Truckstop Location in default and the payment provisions in Section 13(c) shall apply.

(c) On the effective date of any termination (partial or whole) of this Supply Contract, funds owed by Buyer to Seller with respect to the affected Truckstop Location(s), including: (i) amounts owing to Seller for Buyer’s purchases of Seller’s products, and (ii) any other amounts outstanding, shall become immediately due and payable to Seller.

If Seller defaults under this Supply Contract, Buyer shall provide written notice to Seller and Seller shall have thirty (30) days to cure such default; thereafter, if the default continues, Buyer may terminate this Supply Contract upon providing thirty (30) days written notice to Seller.

18. Notices. All notices under this Supply Contract, except those under Section 6 and Section 21, must be in writing and delivered personally or sent by certified mail or by courier service with receipted delivery, to the addresses set forth below, unless such addresses are changed by notice in accordance with this Section 18. Notice by U.S. mail is effective three (3) days from the postmark date. Notice by receipted delivery service is effective as indicated on the signed receipt.

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EXECUTED as of the Effective Date of Amendment No 1, as specified above.

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