general problems of the 2002 Lexus IS300

The contact owns a 2002 Lexus Is300. The contact states the vehicle stalls and will not accelerate, the check engine light will come on either on the highway or on off roads. The vehicle will stall at decelerating or accelerating. The only warning prior to this failure is the check engine light coming on. This occurs at various speeds. The engine will restart usually immediately after the failure. It happened about 100-150 times. The car has been to the dealership about 10 times within the last year. The dealership has attempted to repair the vehicle, but has been unsuccessful. The transmission is automatic.