July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Symptom Related Diagnostic Procedures

Connect a Scan Tool to the ALDL Connector. Drive the vehicle. Observe the Speedometer and Scan Tool speed display.
^ If the Speedometer and Scan Tool agree, check the ECM MEM-CAL, the Vehicle Speed Sensor, and for the correct tire size.
^ If the Speedometer and Scan Tool disagree, service the Instrument Cluster.