ok i own a 2000 trans am automatic it has about 31,000 miles on it and the car never shifts right.. like if im drivin normal and have it in drive it always shifts never slips or anything or if i use 1 2 3 and d it shifts fine. but when i get on it its a diffrent story.. if im at like 20 and in D znd pound it it will go all the up to the rev limiter and bounce off it for like 2-3 seconds then shift and if i manually shiuft it from like 1-2 the shift from 1-2 is perfect but the shift from 2-3 when im on it will go to red line and doesnt shift till i let off the gas kills me in races whats wrong?