Common wisdom tells us to never buy the first production year of any automobile, since that’s when all the bugs not found in pre-production testing tend to surface. In the case of a car as anticipated as the Scion FR-S (or Subaru BRZ), sometimes emotion wins out over common sense.

As early buyers of the FR-S and BRZ are finding out, some cars aren’t quite flawless in execution. Autoweek reports that owners of early production models from both manufacturers are reporting intermittent rough idle and engine stalling issues related to ECU programming.

The good news, then, is that the problem isn’t mechanical or electrical in nature, and the fix could be as easy as having a dealer upload a new ECU program. We say “could be,” as Scion and Subaru differ in their approach to a fix.

Per Scion (Toyota, actually), cars with less than 100 miles on the odometer can simply have the ECU reprogrammed. Since the ECU “learns” a driver’s behavior in the first 100 miles, cars with more than that on the odometer will get a new ECU, loaded with the current program.

Subaru, on the other hand, believes that an ECU re-flash is all that’s needed, regardless of mileage. While we’re not sure which automaker is correct, we’re guessing that the results of the dealer service will quickly determine if reprogramming solves the issue.

Cars delivered to dealerships as of mid-August should already have the new ECU program loaded, and not every early-production car has exhibited the rough-idle problem. In the grand scheme of things, we’re sure this will turn out to be a minor issue for both Scion and Subaru.