Test Drive: Going hybrid makes Tahoe a treat

— -- General Motors plans to start selling gasoline-electric hybrid versions of its full-size Chevrolet Tahoe and GMC Yukon SUVs this fall, hoping their improved fuel economy will attract mileage-minded buyers back to the potentially profitable big SUV market.

A few hours in a preproduction Tahoe hybrid around Northern Virginia, in traffic and on highways, was satisfying.

Tahoe was smooth as you please in stop-go because the electric motor, which handles low-speed driving, provides all its power the instant it begins to turn. Gasoline engines have to rev a bit. GM says the electric-only mode could take you to 32 mph under ideal conditions. But the test showed that accelerating in traffic means electric-only lasts only up to about 10 mph.

The hybrid tows less, 6,000 to 6,200 pounds vs. 7,500 to 8,200 on gasoline models. No tow test was scheduled, but a stop at the Hobby Hangar in Chantilly, Va., a store that sells remote-control cars, planes and boats, provided an opportunity. The folks there, beyond all reason and good sense, offered the store's trailer. It was empty and probably weighed 1,000 pounds, according to the consensus, but it at least hinted how the hybrid would tug.

Very well, it turns out, with the trailer behind and five guys aboard the Tahoe.

Towing or otherwise, under hard throttle the hybrid was quieter than normal Tahoes and felt as if it weren't gaining speed fast. But it was. About the time your rump said 50 mph, the speedometer showed 70. What seemed 35 or 40 mph was 50 mph or faster.

Typical of hybrids, Tahoe saves fuel by shutting off its gasoline engine at stoplights and when the electric motor is sufficient to power the truck. But also unfortunately typical, Tahoe's gasoline engine shuddered as it fired up and began contributing power. Expect the shakes to be gone in regular production models, says Mark Cieslak, chief engineer for GM's full-size trucks.