
Revealing mistake: When Draven sends T-bird to his death in his car, the real Ford Thunderbird is replaced by a fake mockup using a flimsy one-piece fiberglass body mounted on a pair of straight axles. When it explodes, the body lifts off in one piece, warping wildly while the front axle simply falls away. No proper car components like engine, transmission, suspension and so on, are seen anywhere, though they should be. (00:57:05)
Answer: There is no explaination given in the films, they are just brought back when the crow feels it is the right time to avenge their murder.