Please fill out the following to ask a question. MAKE: Toyota MODEL: Highlander YEAR: 2004 MILES: 140,000 ENGINE: 2.4l DESCRIBE ISSUE.... Sporadic misfire / power loss during low-end acceleration / power application: The "hesitation" happens just off-idle when the vehicle is stopped and the accelerator is applied for a normal acceleration, but only at the first quarter of the pedal. If you accelerate a little harder, you can "push past" the "dead spot" and no hesitation occurs. Likewise, if I accelerate in an easy way, there is no problems. This issue also will sporadically set the following codes: P0300, P0301-4, P0420, P0430, The misfire faults (P3001-4) jump from cylinder-to-cylinder, and the CAT efficiency code (Po420/P0430) jumps back and forth between bank-1 & bank-2. The problem rarely occurs when the engine is cold, and is more likely to happen during the warm/hot summer months. I have replaced the MAS (Mass Airflow Sensor, all 4 coils and plugs, and ran several fuel-injector cleaning treatments with no noticeable improvements. There is no other misfire or hesitation at any other power settings, only during initial acceleration from stop. Also, if I "power-brake", I can induce the problem, but it doesn't always result in setting any of the previously mentioned fault codes.