Just bought this minivan, no problems on the test drive, but when we gassed up to go home we lost power on the freeway for a few minutes (flooring it we could barely make 25mph and it would lurch horribly) but got it to restart and run. Ran perfectly fine until today (5 days later) when we put new gas in the tank after driving for about 15-20 minutes. Lost power again about 30 yards from gas station and then it completely stalled and won't start. Turns over, but won't really start -- will barely rev up and then dies again. Tried a gas additive, hasn't helped yet. This is a flex-fuel van, but we used regular gas because we don't have a station w/e85 near us. Dealer told us he had used both kinds of gas and it would "shimmy" after changing fuel types, but would then drive fine. This seem to be what we experienced after the first fill-up on the freeway, but now it won't start at all. Wondering if it's the fuel filter or a problem with the O2 sensor? Maybe?