THOMAS NICOLOSI

We have a 2006 93 arc convertable with a cold start rich issue/ random misfire codes vin YS3FD79Y466108491 , 78000 miles. Our 1st issue was a random flooding problem which made the vehicle undrivable. Added a used ecu to car and now once it gets over the cold rich isssue , runs great. We also repl the coolant temp sensor and plugs. Someone mentioned that if using a used ecu that the 8th digit in the vin must match ??. Mine of course is a y. Any ideas? Tom