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                                                                   EXHIBIT 99.4

                 FIRST AMENDMENT TO MOTORVAC TECHNOLOGIES, INC.
                         1996 STOCK INCENTIVE AWARD PLAN

        THIS FIRST AMENDMENT TO MOTORVAC TECHNOLOGIES, INC. 1996 STOCK INCENTIVE
AWARD PLAN (the "First Amendment") is hereby adopted by Motorvac Technologies,
Inc., a Delaware corporation (the "Company"), effective as of August 15, 1996.

                                 R E C I T A L S

        A. The Motorvac Technologies, Inc. 1996 Stock Incentive Award Plan (the
"Plan") was adopted by the Board of Directors of the Company (the "Board") and
approved by the written consent of the stockholders of the Company in February
1996.

        B. Article XIII of the Plan provides that the Board may amend the Plan
at any time, subject to the approval of the stockholders of the Company in
certain circumstances, none of which apply to the amendments being effected
hereby.

        C. The Board of Directors has determined that it is in the best
interests of the Company and its stockholders to amend the Plan in order to (i)
provide that Incentive Awards (as defined in the Plan) shall become exercisable
in full upon the occurrence of a Terminating Transaction (as defined in the
Plan) and (ii) conform the provisions of the Plan to the recently adopted
amendments to Rule 16b-3 ("Rule 16b-3"), promulgated under the Securities and
Exchange Act of 1934, as amended (the "Exchange Act").

                                    AMENDMENT
1.      CAPITALIZED TERMS.

        Capitalized terms used herein without definition shall have the same
meanings given to such terms in the Plan.

2.      AMENDMENTS.

        The Plan is hereby amended as follows:

        (a) The definition of "Disinterested Person" in Article II of the Plan
is hereby deleted and is replaced with the following definition: "NON-EMPLOYEE
DIRECTOR. The term "Non-Employee Director" shall mean a Non-Employee Director as
that term is defined in Rule 16b-3." Each reference to the term "Disinterested
Person" in the Plan shall hereafter be amended to refer to a "Non-Employee
Director."

        (b) The definition of "Eligible Person" in Article II of the Plan is
hereby amended and restated to read in its entirety as follows: "ELIGIBLE
PERSON. The term


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"Eligible Person" shall mean any employee, consultant, officer or director of
any Participating Company, including officers who are directors."

        (c) Section 6.03(a) of the Plan is hereby amended to read in its
entirety as follows: "(a) VESTING. The Board (or the Committee, if applicable)
shall determine when a Right shall vest or become exercisable, provided that
from and after such time as the Common Stock is registered under the Exchange
Act and, to the extent necessary to comply with the provisions of Rule 16b-3, no
Right granted under this Plan shall be exercisable until six months and one day
after the Right Grant Date."

        (d) Section 6.03(b) is hereby amended and restated to read in its
entirety as follows: "(b) RULE 16b-3 LIMITATIONS. The Board (or the Committee,
if applicable) may, at the time a Right is granted, impose such conditions on
the exercise of a Right as may be required to comply with Rule 16b-3 (or any
successor provision) to the extent such provision is applicable."

        (e) Section 7.01(c) is hereby amended so that the second sentence of
such section is deleted in its entirety.

        (f) Section 7.01(e) is hereby deleted in its entirety.

        (g) Section 8.01(c) is hereby amended so that the second sentence of
such section is deleted in its entirety.

        (h) Section 8.01(f) is hereby deleted in its entirety.

        (i) Article IX(b)(v) is hereby deleted in its entirety and the phrase
")other than those imposed under subparagraph (b)(v))" in Article IX(c) is
hereby deleted.

        (j) Article X is hereby amended so that the last sentence of such
article is deleted in its entirety.

        (k) Article XI is hereby amended so that the last sentence of such
article is deleted in its entirety.

        (l) Section 14.01(b) is hereby amended to read in its entirety as
follows: "The Right Termination Date or Option Termination Date, as applicable."

        (m) Section 14.06 is hereby amended and restated in its entirety to read
as follows:

        "14.06 INCENTIVE STOCK OPTIONS NOT TRANSFERABLE. Incentive Stock Options
granted under this Plan may not be sold, pledged, hypothecated, assigned,
encumbered, transferred by gift or otherwise transferred or alienated in any
manner, either voluntarily or involuntarily, or by operation of law, other than
by will or the laws of


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descent and distribution, and may be exercised during the lifetime of a
Participant only by such Participant. Upon any attempt to transfer Incentive
Stock Options other than by will or the laws of descent and distribution, or to
assign, pledge, hypothecate or otherwise dispose of Incentive Stock Options, or
upon the levy of any execution, attachment or similar process thereon, such
Incentive Stock Options shall become null and void and any subsequent attempted
exercise of the Incentive Stock Options shall be ineffective against the
Company. Any other Incentive Award (other than an Incentive Stock Option or a
Right granted in tandem with an Incentive Stock Option ) may be assigned in
whole or in part in accordance with the terms of the applicable Option
Agreement. The terms of the Incentive Awards shall be binding upon the
executors, administrators, heirs, devisees, legatees, legal representatives,
successors and assigns of the Participants." 

        (n) Section 14.09 is hereby amended and restated in its entirety to read
as follows:

        "14.09 ACCELERATION UPON A TERMINATING TRANSACTION. Upon the occurrence
of a Terminating Transaction and for a period of ten (10) days thereafter,
Participants holding outstanding Incentive Awards shall have the right to
exercise his or her Incentive Awards to the full extent not theretofore
exercised, including any Incentive Awards which have not yet become Vested
Incentive Awards (subject, however, to the provisions of Sections 6.03(a) and
8.01(d) above). For purposes of determining the cash payment pursuant to Section
6.04(a) hereof upon an exercise of a Right: the Fair Market Value of a share of
Common Stock on the Exercise Date shall equal the highest reported sales price
of a share of Common Stock within the sixty (60) day period immediately
preceding the date of the Terminating Transaction, as reported on any securities
exchange or quotation reporting system upon which the shares of Common Stock are
traded or included."

3.      MISCELLANEOUS.

        Except to the extent set forth herein, the Plan shall remain unchanged
and in full force and effect. This First Amendment shall be governed by and
construed in accordance with the laws of the State of California and may only be
amended by a written instrument executed on behalf of the Company. In the event
of any inconsistency between the terms of this First Amendment and the terms of
the Plan, the terms of this First Amendment shall control.

        I hereby certify that the foregoing First Amendment was duly adopted by
the Board of Directors of the Company on August 15, 1996.

        Executed as of this 15th day of August, 1996.


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                                            Allan T. Maguire, Secretary


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