 Auto Parts. Improve or maintain your vehicle's performance with Lucas Fuel Treatment at O'Reilly Auto Parts. Simply add it to your tank at your next fill up to eliminate carbon and varnish deposits. A clean fuel system can also maintain or improve fuel economy. Right now, get two bottles of Lucas Fuel Treatment for just $9. You'll also receive two times O'Rewards points to help you get to your next reward faster. In-store only at your local O'Reilly Auto Parts.