Fabi returned to Indy car racing in 1988 with Porsche Motorsports in their No. 8 Quaker State March 88P-Porsche Indy V8. The Porsche engine was less competitive than the Ilmor-Chevrolet and Cosworth engines. Despite the setbacks Fabi managed a best finish of fourth at the Bosch Spark Plug Grand Prix at Pennsylvania International Raceway. Fabi's return to the Indianapolis 500 was also a disappointment as he qualified seventeenth and finished thirtieth after losing a wheel after 30 laps. He ended the season ranked tenth with 44 points.