After a brief retreat, gas prices are on the rise again. And that could be bad news for the auto industry. Sales of full-size sport-utility vehicles are already showing signs of what industry executives euphemistically call "softness." Bottom line, sales are tumbling. That's particularly bad news for Detroit, which heavily depends on light truck sales, including GM, which is just getting ready to launch an assortment of new full-size trucks, such as the 2007 Chevrolet Tahoe and Cadillac Escalade sport-utility vehicles. But the situation is starting to worry some of the imports, as well. There's Audi, which was late to the party and is just introducing its first sport-ute, the Q7. Even the Asians are starting to feel the impact of rising oil prices. Nissan officials tell TheCarConnection.com they're cutting back production at their Mississippi assembly plant, which produces such big truck models as the Titan pickup and Armada SUV. It's starting to seem like fuel prices have finally reached a point where they're affecting everyone's buying decision.