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                                                                   EXHIBIT 3.18

                                     BYLAWS

                                       OF

                           SUPER TEST PETROLEUM, INC.


                                    ARTICLE I

                                 Shares of Stock

         1.1 Certificate of Shares. The certificates of shares of capital stock
of the Corporation shall be in such form as shall be approved by the Board of
Directors and as shall be required by law. The certificates of shares shall be
signed by the Chairman of the Board, Vice-Chairman of the Board, President or a
Vice-President and may also be signed by another officer of the Corporation. The
certificates may be sealed with the seal of the Corporation or a facsimile
thereof.

         1.2 Transfer of Shares. Shares of capital stock of the Corporation
shall be transferred by endorsement of the certificates representing said shares
by the registered holder thereof, or by his legal representative, who shall
furnish proper evidence of authority to transfer, or by his attorney who shall
be authorized by a Power of Attorney which is duly executed and filed with the
Secretary of the Corporation, and by the surrender of the shares to the
Secretary for cancellation. The person whose name is listed on the books of the
Corporation as the owner of the shares shall be deemed by the Corporation to be
the owner thereof for all purposes.

         1.3 Lost Certificates. In the event of loss of stock certificates, new
certificates shall be issued only upon proof of loss by affidavit by the
registered holder and approval by the Board of Directors, who may require a Bond
of Indemnity in a form satisfactory to them as a condition thereof.

         1.4 Fixing of Record Date. For the purpose of determining shareholders
entitled to notice of and to vote at a meeting of shareholders or an adjournment
of a meeting, the Board may fix a record date which shall not precede the date
on which the resolution fixing the record date is adopted by the Board. The date
shall be not more than sixty (60) nor less than ten (10) days before the date of
the meeting. If a record date is not fixed, the record date for determination of
shareholders entitled to notice of or to vote at a meeting of shareholders shall
be the close of business on the day next preceding the day on which notice is
given, or if no notice is given, the day next preceding the day on which the
meeting is held. When a determination of shareholders of record entitled to
notice of or to vote at a meeting of shareholders has been made as provided in
this section, the determination applies to any adjournment of the meeting,
unless the Board fixes a new record date under this section for the adjourned
meeting.
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         For the purpose of determining shareholders entitled to express consent
to or to dissent from a proposal without a meeting, the Board may fix a record
date which shall not precede the date on which the resolution fixing the record
date is adopted by the Board and shall not be more than ten (10) days after the
Board resolution. If a record date is not fixed and prior action by the Board is
required with respect to the corporate action to be taken without a meeting, the
record date shall be the close of business on the day on which the resolution of
the Board is adopted. If a record date is not fixed and prior action by the
Board is not required, the record date shall be the first date on which a signed
written consent is delivered to the Corporation pursuant to Section 407 of the
Michigan Business Corporation Act, as amended, or any successor provision.

         For the purpose of determining shareholders entitled to receive payment
of a share dividend or distribution, or allotment of a right, or for the purpose
of any other action, the Board may fix a record date which shall not precede the
date on which the resolution fixing the record date is adopted by the Board. The
date shall not be more than sixty (60) days before the payment of the share
dividend or distribution or allotment of a right or other action. If a record
date is not fixed, the record date shall be the close of business on the day on
which the resolution of the Board relating to the corporate action is adopted.

         1.5 Dividends. The Board of Directors may, from time to time, declare
and the Corporation may pay dividends on its outstanding shares in the manner
and upon the terms and conditions provided by law and its Articles of
Incorporation.

                                   ARTICLE II

                                  Shareholders

         2.1 Annual Meeting. The annual meeting of the shareholders shall be
held at a time and place designated by the Board of Directors. The purpose of
the annual meeting shall be to elect Directors, and to transact such other
business as may come before the meeting.

         2.2 Special Meeting. Special meetings of the shareholders may be called
by the President or Secretary and shall be called by either of them on the
request in writing or by vote of one or more shareholders of record owning a
majority of the issued and outstanding shares of capital stock of the
Corporation.

         2.3 Notice of Meeting. Written notice of the time, place and purpose of
any shareholders' meeting shall be given to each shareholder, either personally
or by mail, not less than ten (10) days nor more than sixty (60) days before the
meeting. If mailed, notice shall be deemed given by depositing the same in a
post office box, postage prepaid, and addressed to the last-known address of
such shareholder.


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         2.4 Quorum of Shareholders. Except as hereinafter provided and as
otherwise provided by law, at any meeting of the shareholders, a majority in
interest of all the capital stock issued and outstanding, represented by
shareholders of record in person or by proxy, shall constitute a quorum. The
shareholders present in person or by proxy at such meeting may continue to do
business until adjournment, notwithstanding the withdrawal of enough
shareholders to leave less than a quorum. Less interest than a quorum may
adjourn any meeting.

         2.5 Voting. Each outstanding share is entitled to one vote on each
matter submitted to a vote, unless otherwise provided in the Articles of
Incorporation. A vote may be cast either orally or in writing. When an action,
other than the election of Directors, is to be taken by vote of the
shareholders, it shall be authorized by a majority of the votes cast by the
holders of shares entitled to vote thereon, unless a greater plurality is
required by the Articles of Incorporation or by law. Except as otherwise
provided by the Articles of Incorporation, the Directors shall be elected by a
plurality of the votes cast at an election of Directors.

         2.6 Proxies. Shareholders of record may vote at any meeting either in
person or by proxy in writing, which shall be filed with the secretary of the
meeting before being voted. Such proxies shall entitle the holders thereof to
vote at any adjournment of such meeting, but shall not be valid after the final
adjournment thereof. No proxy shall be valid after the expiration of three (3)
years from the date of its execution unless the shareholder executing it shall
have specified therein the length of time it is to continue in force, which
shall be for some limited period.

         2.7 Waiver of Notice. Attendance of a person at a meeting of
shareholders, in person or by proxy, constitutes a waiver of notice of the
meeting, except when the shareholder attends a meeting for the express purpose
of objecting, at the beginning of the meeting, to the transaction of any
business because the meeting is not lawfully called or convened.

         2.8 Consent in Writing. Any action required or permitted to be taken at
an annual or special meeting of shareholders may be taken without a meeting,
without prior notice, and without a vote, if before or after the action all the
shareholders entitled to vote consent in writing.

         2.9 Electronic Meetings. The shareholders may participate in a meeting
of the shareholders by means of conference telephone or similar communications
equipment by means, of which all persons participating in the meeting can hear
each other. Participation in a meeting pursuant to this Section shall constitute
presence in person at the meeting.

         2.10 Conduct of Meetings. Meetings of shareholders generally shall
follow accepted rules of parliamentary procedure, subject to the following:

                  (a) The Chairperson of the meeting shall have absolute
authority over matters of procedure, and there shall be no appeal from the
ruling of the Chairperson. If, in his or her absolute discretion, the
Chairperson deems it advisable to dispense with the rules of parliamentary


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procedure as to any one meeting of shareholder so part thereof, he or she shall
so state and shall clearly state the rules under which the meeting or
appropriate part thereof shall be conducted.

                  (b) If disorder should arise which, in the absolute discretion
of the Chairperson, prevents the continuation of the legitimate business of the
meeting, the Chairperson may quit the chair and announce the adjournment of the
meeting, and upon his or her so doing, the meeting shall be immediately
adjourned without the necessity of any vote or further action of the
shareholders.

                  (c) The Chairperson may require any person who is not a bona
fide shareholder of record on the record date, or a validly appointed proxy of
such a shareholder, to leave the meeting.

                  (d) Except as the Chairperson shall direct, a resolution or
motion shall be considered for vote only if proposed by a shareholder of record
on the record date or a validly appointed proxy of such a shareholder, and
seconded by such a shareholder or proxy other than the individual who proposed
the resolution or motion.

                  (e) Unless otherwise provided in the Articles of Incorporation
or directed by the Chairperson, no matter may be presented to the meeting which
has not been submitted for inclusion in the agenda within ten (10) days after
the date written notice of the meeting is mailed to the shareholders.

                                   ARTICLE III

                               Board of Directors

         3.1 Number, Term, and Qualifications. The business and affairs of the
Corporation shall be managed by its Board of Directors. The number of Directors
on the first Board of Directors shall be one (1). Thereafter, the number of
Directors of the Corporation may be changed from time to time, as determined by
the Board of Directors or shareholders of the Corporation. A Director need not
be a shareholder. Each Director shall hold office for the term for which he is
elected and until his successor shall have been elected and qualified or until
his resignation or removal.

         3.2 Nominations of Director Candidates. Members of the Board of
Directors of the Corporation shall be nominated as follows:

                  (a) Nominations of candidates for election to the Board of
Directors of the Corporation may be made by the Board of Directors or by any
shareholder entitled to vote for election of Directors.


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                  (b) Nominations made by the Board of Directors shall be made
at a meeting of the Board of Directors, or by written consent of the Directors
in lieu of a meeting, at any time prior to the date of any meeting of
shareholders called for the election of Directors, and such nominations shall be
reflected in the record books of the Corporation as of the date made.

                  (c) Nominations made by a shareholder entitled to vote for
election of Directors shall be made in writing and shall be delivered to the
Secretary of the Corporation not less than fourteen (14) nor more than fifty
(50) days prior to the date of any meeting of shareholders called for the
election of Directors provided, however, that if less than twenty-one (21) days'
notice of the meeting is given to shareholders, such nominations shall be
delivered to the Secretary of the Corporation not more than seven (7) days
following the date of such notice. Such nominations shall set forth: (1) the
name, age, business address and residence address of each nominee; (2) the
principal occupation or employment of each nominee; (3) the number of shares of
capital stock of the Corporation beneficially owned by each nominee; (4) the
total number of shares of capital stock of the Corporation that will be voted
for each nominee; (5) the name, business address and residence address of the
nominating shareholder; (6) the number of shares of capital stock of the
Corporation owned by the nominating shareholder; (7) a statement that each
nominee is willing to be nominated; and (8) such other information concerning
each nominee as would be required under the rules of the Securities and Exchange
Commission in a proxy statement soliciting proxies for the election of such
nominees.

                  (d) If a nomination was note made in accordance with the
foregoing procedures, such nomination shall be void and all votes cast in favor
of a person so nominated shall be disregarded.

         3.3 Meetings. Regular meetings of the Board of Directors shall be held
either with or without notice, at such times and such places as any of the
Directors may by resolution from time to time determine. Special meetings of the
Board of Directors shall be held whenever called by the President; or when the
President shall be required to call a special meeting upon written request by
any Director. Due notice of any special meeting, which may be waived, shall be
given by the Secretary, in writing, not later than the day preceding the
meeting. A Director's attendance at, or participation in, a meeting constitutes
a waiver of notice of the meeting, except where, at the beginning of the meeting
or upon his arrival, the Director objects to the meeting or the transacting of
business at the meeting and does not thereafter vote for or assent to any action
taken at the meeting. A member of the Board or a committee designated by the
Board may participate in a meeting by means of conference telephone or similar
communications equipment by means of which all persons participating in the
meeting can hear each other. Participation in a meeting pursuant to this method
constitutes presence in person at the meeting.

         3.4 Quorum. A majority of the members of the Board then in office, or
of the members of a committee thereof, constitutes a quorum for the transaction
of business.


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         3.5 Voting. The vote of the majority of members present at a meeting at
which a quorum is present constitutes the action of the Board or of the
committee.

         3.6 Vacancies. Vacancies in the Board of Directors, including a vacancy
resulting from an increase in the number of Directors, may be filled by either
the shareholders or the Directors. If the Directors remaining in office
constitute fewer than a quorum of the Board, they may fill the vacancy by the
affirmative vote of a majority of all Directors remaining in office.

         3.7 Action Without a Meeting. Action may be taken by the Board of
Directors or a committee thereof without a meeting if, before or after the
action, all members of the Board then in office or of the committee consent
thereto in writing. The written consent shall be filed with the minutes of the
proceedings of the Board or committee.

         3.8 Removal of Directors. A Director or the entire Board may be
removed, with or without cause, by vote of the holders of a majority of the
shares entitled to vote at an election of Directors.

         3.9 Electronic Meetings. The Board of Directors or any committee
designated by the Board of Directors may participate in a meeting of such Board,
or committee, by means of conference telephone or similar communications
equipment by means, of which all persons participating in the meeting can hear
each other. Participation in a meeting pursuant to this Section shall constitute
presence in person at the meeting.

                                   ARTICLE IV

                                    Officers

         4.1 Officers. The officers of this Corporation shall consist of a
President, a Secretary, a Treasurer, and if desired, a Chairman of the Board and
one or more Vice Presidents, who shall be elected by the Board of Directors at
the annual meeting held immediately after the adjournment of the regular annual
meeting of the shareholders. The Board of Directors may also appoint such other
officers and agents as they shall deem necessary for the transaction of business
of the Corporation. An officer shall hold office for the term for which he is
elected or appointed and until his successor is elected or appointed and
qualified, or until his resignation or removal. Two or more offices may be held
by the same person, but an officer shall not execute, acknowledge or verify an
instrument in more than one capacity, if the instrument is required by law, or
the Articles of Incorporation, or these Bylaws, to be executed and acknowledged
or verified by two or more officers.

         4.2 Duties of Officers. The officers of the Corporation shall be
charged with such duties and authority as usually appertains to such offices in
a Corporation, except that said duties may be varied or added to by the Board of
Directors.


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         4.3 Removal of Officers and Agents. Any officer or agent may be removed
by the Board of Directors whenever in its judgment the business interests of the
Corporation will be served thereby.


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                                    ARTICLE V

                                   Fiscal Year

         5.1 Fiscal Year. The Corporation's fiscal year shall be as determined
from time to time by the Board of Directors.

                                   ARTICLE VI

                                   Amendments

         6.1 Amendments. These Bylaws may be altered or amended by the
shareholders or the Board of Directors. Amendment of the Bylaws by the Board
requires the vote of not less than a majority of the members of the Board then
in office.


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