(CNN) -- American Robby Gordon faces disqualification from the Dakar Rally after stewards recommended his removal from the race because his Hummer's engine does not conform to regulations.
The 43-year-old appeared the main challenger to car leader Stephane Peterhansel after winning both Monday and Tuesday's stages, cutting the French driver's advantage to almost six minutes.
However, the ultimate decision over Gordon's fate rests with the French Automobile Sport Federation (FFSA), who must deliver their verdict within two months, although the loser could still appeal to motorsport's global governing body, the FIA, should he be thrown out of the race.
The stewards believe that Gordon's modifying of the ventilation system, linked to his engine, improves its performance level -- a claim he denies.
That appeal allowed Gordon to continue racing in the 377-kilometer 10th stage from Iquique to Arica in Chile, although his hopes took a further knock as he subsequently lost 15 minutes to stage winner Nani Roma of Spain after suffering damage to his car.
"I hit a rock with both right-side tires and, as you can see, this wheel is way out, so we've got some broken parts," Gordon told reporters.
Roma's victory means he leapfrogs Gordon into second place overall, a massive 19 minutes and five seconds behind fellow Mini driver Peterhansel.
Gordon is another 46 seconds adrift in third with just four stages remaining.
Former motorbike star Peterhansel is bidding for a remarkable 10th overall win in the race and a fourth in the car section.
Meanwhile, just 16 seconds now separate KTM riders Cyril Despres and Marc Coma in the motorcycle section after Wednesday's stage, which was won by Joan Barreda Bort.
Defending champion Coma finished second to his fellow Spaniard on the day, while France's Despres came home fourth.
"It's the tone that's been set for the rally and I think we'll keep on battling until the end," Roma told reporters.
Both riders have won the race three times, alternating victory between each other over the last six seasons.