Here we go again. After that remark we made last year, the one about Jeep selling Cherokees until we are old and gray, it now appears that the Cherokee's life span will continue for awhile longer. Due to "overwhelming customer demand," the Jeep people now tell us, "Cherokee production is extended past the original November 2000 close." We've heard this before. The Grand Cherokee was supposed to replace the Cherokee, but due to the demand for this solid, inexpensive SUV, they kept making them. Now, they're coming out with another, smaller SUV that is supposed to replace the Cherokee. But people keep buying them. So there is going to be a 2001 model, but after that, who knows? Jeep is eager to introduce newer, more modern, more aerodynamic products, such as the upcoming Liberty. You might want to wait and see what develops. Or you might want to buy a classic while you still can. The four-cylinder Cherokee is already gone, which partially explains this year's significantly higher base price. All 2001 Cherokees will be powered by a 4.0-liter, overhead-valve inline-6. This is the same engine that was re-designed last year for 50-state LEV (low-emissions vehicle) certification. Cherokee is a case study in how long a solid design can remain viable. Introduced in 1984, Cherokee helped launch America into its amazing romance with sport-utility vehicles. Cherokees sprouted in suburban driveways like mushrooms. And its popularity continues. Jeep sold more than 140,000 Cherokees last year. And why not? Cherokee is still tough as nails, reasonably inexpensive and, in four-wheel-drive guise, thoroughly capable when the pavement ends. More than that, its flat-planed, square-edged styling resonates with all the richness of Jeep history.