93 Prizm a/t no first gear

I have a 1993 Prizm LSI a/t, 155,00 miles when the car is in drive it starts out in second gear. This happen at around 85,000 change trans fluid worked fine til now. When shifted to L gear manually first gear is there. OD off light keeps flickering on off when starting in D. Could this be a sensor or some sort of vacumn problem? Hoping I don't need a complete re-built. Any help would be great thanks