i have a 2008 is350 that starts up fine, at idle everything works fine, but when i press the gas/accelerate the car seems to lose power? my headlights flicker on and off, the lights on my dash come on and off, the compass in the rear view mirror goes crazy, radio stays powered on but no sound, and the speedometer goes up and down no matter how fast or slow i'm going etc. so far i changed the battery and alternator but i'm still having the same issue and its driving me crazy! anyone have an idea as to what the problem could be?