I don't think its a hoax.
They used the same technology in WWII and that wasn't a hoax.
I just did a google and saw a pic of a wood-powered tractor plowing a field. Apparently you can burn wood, take off the gas, pipe it directly into the carberator, and run the engine. In fact, here is a manual telling how to pimp your ride into a wood-powered car.
Wood gas
Wood gas as motor fuel
The Gengas Page -- Fuel gas, produced by the reduction of coal and peat, was used for heating as early as 1840 in Europe, and by 1884 it had been adapted to fuel engines in England. Petroleum shortages during World War II led to widespread gas generator applications in the transportation industries of Western Europe. (Charcoal-burning taxis, a related application, were still common in Korea as late as 1970.) This report attempts to preserve the knowledge about wood gasification as put into practical use during World War II. Detailed, step-by-step procedures are presented in this report for constructing a simplified version of the World War II, Imbert wood gas generator. Full text online.
http://www.gengas.nu/byggbes/index.shtml