Hyundia accelerates slowly

After the car sits over night or for a long time the car has trouble accelerating. The gas pedal would be all the way down on the floor, but the car would barely move until it would just kick in and go. This problem only happens in the summer. This also happens on my Sonata. Finally on more thing the windshield wipers sometimes move vary slowly even on the highest level. Could there be an electric problem?

Thanks