The Napa County Sheriff's Department has tentatively identified James Grobl as the person found in the car. The Jeep was located in a driveway leading to Grobl's home.
Sheriff's Capt. John Robertson said dental records would be used to positively identify the burn victim.
Cal Fire crews found the body in the burned Jeep after extinguishing a one-acre brush fire in the 1600 block of Mount Veeder Road in west Napa County, Battalion Chief David Shew said. The fire was reported at 12:30 a.m. Saturday.
The Jeep apparently was stopped across the driveway, its rear wheels resting on a downward slope, Shew said.
It appears the driver spun the Jeep's wheels, trying to free the vehicle, and that a spark from that friction could have caused the brush fire, Shew said. Hot exhaust could also have started the fire, he said.
"The Jeep caused the fire but we don't know why," Shew said.
The lights were on at the house at the end of the driveway, and the home's doors were open, Shew said. Grobl, 66, was retired.