Could be many things like low battery power,low float levels, leak fuel pump, stuck tank vent check valve, incorrect valve lash, low compression, other power issues line bad buss connector as all 05's had, valve timing problem, warn cam lobes. It could also be a problem with the CVT system or even the rear wet brakes if the pinion nut had backed off like it has done with so many hundreds. Start with this list and check them off as you go. If you don't have a service manual..get one.