Without Scan Tool

Resetting Keep Alive Random Access Memory (RAM)
Disconnect the negative (-) lead from the battery for 5 - 10 minutes (this will also result in the PCM reset described above). Resetting keep alive Random Access Memory (RAM) will also clear learned values the PCM has stored for adaptive systems such as Idle and Fuel. Once the vehicle is driven the PCM will relearn new adaptive values. It will take a few miles and the vehicle may run rough until the values are relearned.