Dick, Most common, As the 02 sensor gets old, the voltage changes going to the Lambda ECU, the air / fuel mixture will change. Then the 02 will try to adjust which causing it to seek along with a few other things like Dave mentioned. After it warms up, you can adjust the air flow meter to smooth out as long as there are no other problems. If the 02 sensor is new, then you have to re adjust the air flow meter to the new conditions. The computers in the cars today do it automatically. Untill the De Lorean gets a highter level of computer, it's a 3mm long allen ever so often. John Hervey www.specialTauto.com