Sebastien Loeb grabbed victory Sunday in the eighth stage of the Dakar Rally after Carlos Sainz was hit with a five-minute penalty.   The victory lifted Loeb to fourth overall but he remains almost two hours behind overall leader Nasser Al-Attiyah.   The 48-year-old Frenchman won the stage by 2 minutes and 11 seconds in his Prodrive from Qatari Al-Attiyah after 822 km of racing through valleys and sand between Al-Duwadimi and Riyadh.  Loeb has had a wildly up-and-down race. After bad days on Monday and Tuesday he won on Wednesday and then rolled his car on Thursday and on Saturday lost more than 16 minutes.  Sainz has also had shifting fortunes in the sands. On Sunday he was caught driving 40 kilometers over the limit in his Audi in a 30kph section. The penalty dropped him to third for the day at 3min 31sec.  The Spaniard is 17th overall.   Henk Lategan was fourth in a Toyota at 4min 53sec to tighten his grip on second place but the South African fell 1hr 3min 46sec behind the leader.   Brazilian Lucas Morais is third in another Toyota at 1:20.22 with Loeb fourth, 1:52.06 off first.   Monday is a rest day before the competitors hit the road again on Tuesday for the final six stages.   In the motorbikes, Ross Branch made amends for running out of fuel in the previous two stages with a welcome win.   After Saturday's washout, when torrential rains trashed the route, the bikers were back into a mesh of stony valleys and massive sand dunes.   Branch, from Botswana, completed the course on his Hero 3min 15sec ahead of the Australian Daniel Sanders (GasGas).   "It's been a terrible week for us," said 36-year-old Branch.   "We ran out of fuel, which was completely unexpected and nobody's fault.   "I needed to get back on top for myself and for the team. They've worked so hard.   "We've been perfect today and that's what counts."   Sanders, who lost the overall lead during a disastrous stage on Thursday, benefitted on Sunday from a two-minute penalty handed out to Mason Klein (KTM) for speeding in the road section.   That cost the 21-year-old Californian the overall lead and allowed compatriot Skyler Howes (Husqvana) to retain first place ahead of Monday's rest day.   Howes holds a 1min 13sec lead over Klein, who was given third in the stage.