I have heard that Cadillacs have a diagnostic "snapshot" capability to help track down intermittant problems. The "snapshot" records all the engine data when the driver chooses to do so. I've briefly looked through my manuals and haven't found anything on it. Can someone tell me how to take a "snapshot" on a '94 Eldorado with Northstar engine and how to get a read-out of the data? Thanks in advance.