P0170 is not a "direct" code - it is an adaptation code. In other words, the engine is trying to compensate for something and it is no longer within tolerance. Your symptoms sound like a Mass Air Flow sensor acting up - but your are guessing at things without taking it to someone with a system that will look beyond the OBDII codes and look at actual values and adaptations. Take it to a good shop, otherwise you will only solve your problem by methodical parts-swapping and that gets expensive.