Problem: On acceleration, car pulses very subtly. On deceleration it does the same thing. Occasionally, when going from D to P, idle will surge up above 10k, then gradually come down. Sometimes when this happens, ASR light goes on. Also, more troubling, when driving, the ASR and ABS light come on and acclerator peddle offers no response. In this instance, I shift to N, turn off ignition and turn on and we're back in business. No fault codes to give us a clue.
Solution: After several incremental expendtires (brake light switch, vaccuum hoses, etc.) replaced Throttle Actuator (ouch, $$) and all is well with the world.