Received my used DB7 in January. Started fine off the truck and into the garage but then would only start intermittantly. Starter would work and engine would turn over but not catch. Took it to local Jaguar dealer and they replaced battery but still had the problem of not starting all of the time. Took it to Aston Martin dealership and it turned out that one of the keys had lost its programming. With a bad chip, the key will allow the starter to work but not allow gas to go to engine.

Bill