Despite a big marketing push, hybrid sales for General Motors have been extremely low in the first quarter of 2008. The carmaker now has five hybrids on the market, including the Chevy Tahoe Hybrid, which was designated “Green Car of the Year” by Green Car Journal.

GM eked out 843 hybrid sales from January to March. That number breaks down to 655 Tahoe and Yukon models, 158 Saturn Vues, 20 Saturn Auras, and 10 Chevy Malibus. Total hybrids sales in the first three months of 2008 exceeded 80,000 units.

General Motors said the company is maintaining significantly higher sales projections, including an annual projected volume of 10,000 to 12,000 combined sales for the Chevy Tahoe Hybrid and GMC Yukon hybrids. “Things are starting out slow, but we expect sales to ramp up,” said GM spokesman Brian Corbett, in an interview with HybridCars.com. “We’re holding to our original projections for Tahoe and Yukon.” In order to achieve this goal, GM would need to an approximate four-fold increase in the pace of sales for the rest of the year.

Even if GM were to increase production and distribution of its hybrids, it’s unclear if the company has a winning formula for its hybrids. The Tahoe and Yukon, while offering impressive mileage for a full-size SUV, are priced above $50,000. The other GM hybrids are more moderately priced, but use a mild form of hybrid technology that produces only modest gains in fuel economy. For example, the Chevy Malibu Hybrid, which gives 24 in the city and 32 on the highway as compared to the gas version’s 22 city/30 highway.

Current economic conditions—a pending recession and high gas prices—mean that consumers either want to spend less or get a big benefit from the extra expense. In the case of hybrids, that has to add up to high MPG. Market analysts will be keeping a close eye on GM hybrid sales in April and May, as the company increased production and gas prices reach new record levels.