Many sport-utility buyers like to plant their right feet deep into the accelerator and feel instantaneous movement. Do this in Jeep's redesigned '99 Grand Cherokee Limited and it takes off a bit slower than last year's model. Part of the reason is that the old 5.2-liter V8 engine has been replaced with an all-new 4.7-liter overhead cam V8. The minor loss in acceleration is offset by the refinement of the new engine. It accelerates smoothly, with none of the mechanical grumbling and rude roaring of the previous 5.2-liter and 5.9-liter engines. What you lose at the drag strip, you gain in peace and tranquility. We'd call the big Jeep more mature.