EXHIBIT 99.3 CERTIFICATION PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 (SUBSECTIONS (a) AND (b) OF SECTION 1350 OF TITLE 18, UNITED STATES CODE) Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, (Subsections (a) and (b) of Section 1350 of Title 18, United States Code), I, James J. Postl, President and Chief Executive Officer of the Pennzoil-Quaker State Company, a Delaware corporation, hereby certify, to my knowledge, that: (1) the Company's Quarterly Report on Form 10-Q for the quarter ended June 30, 2002 (the "Report") fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and (2) the information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of the Company. Dated August 13, 2002 /s/ James J. Postl -------------------------------------- James J. Postl President and Chief Executive Officer The foregoing certification is being furnished solely pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, (Subsections (a) and (b) of Section 1350 of Title 18, United States Code) and is not being filed as part of the Report or as a separate disclosure document.