Keep in mind that the ambient temperature reading will almost never match the outside air temp when you are riding. The bodywork traps warm air, and the airflow past the sensor is minimal...especially with foglights installed. If you ride a while, then park while you run into the store, especially in the sun, the ambient air temp will skyrocket when you restart. It should also be noted that the reading is programmed to respond very slowly, so the high reading will adjust to ambient slowly.
The good news is that while this reading is used in the fuel management, it plays a relatively small part. The pressure sensors have more effect. If the sensor is suspect, there are tests your dealer can run. They do allow some variation, however. The best test of the sensor is to see what it reads compared to the air temperature after it has been parked all night, before the Spyder is started. Most read within two degrees of the actual garage temperature. In my experience, the indicated temperature on the open road, say 15 minutes into a ride, will read about 3-5 degrees above the actual, due to the trapped heat. All three of our Spyders have been this way. Only one ran lean. Also keep in mind that the air intake is within the bodywork, too, so the Spyder breathes in the same air that the sensor measures. We would all be better off if the temperature just wasn't displayed, IMO.