06 Altima. Was 0F overnight. Started this morning. Warmed up 15 mins. Backed up, put it in drive, stepped on the accelerator and... nothing. Barely moving. No revving just idle. Best way to describe it is as if the accelerator pedal was disconnected from the throttle. Or a limp. But no codes. Battery was definitely weak but I figured the cold. Fresh oil. New coolant. Transmission fluid is unknown but red in color. Any ideas what to check next?