Just took delivery of new silver Prius IV this week. Wow - what a car! My wife does not like the pokey behavior in eco mode and likes to drive in power mode most of the time. What gas mileage can we expect to obtain if driving mostly in power mode. Also -would driving in power mode adversely impact on the break-in period of the engine. Thanks for your input
Power mode is not going to kill your MPG, erratic driving, short commutes and not anticipating stops is what will kill it. So if she drives like the typical SUv soccer/power mom in my area I would expect you to see low to mid 40s at best in a Gen III. Toss in a terrible commute and you could dip into the 30s.
Only thing power mode does is de-sensitize the gas pedal and allow the AC to run at full capacity. If your rate of acceleration is the same, your mileage will be the same regardless of which mode you select.
I've been running in Power mode for at least three fill-ups, and my mileage is around 44. I suspect hills and decreasing temperatures are bigger factors. I also like the quicker power response than the sluggishness in Normal mode. Search for the thread "I Love Power Mode" for more experiences. That said, one still gas to drive prudently.