daewoo leganza shifting problems in drive!

[daewooblues]

i have a daewoo leganza 1999 and when i put it in drive it acts like it is stuck in 4th gear and want shift down when you take off, and it does not have any power. you can floor it and it want shift down. but you can manualy shift it and it does fine. is there a passing gear cable like on most car or what? i am lost!!! i just got threw rebuilding the top half cause of a broke timing belt and the motor is running fine other than a lope in the idle that goes away when you give it a little gas i think that is the air idle control switch? i have checked the timing and it is dead on. please if anyone has any ideas let me know. on the trans or the idle. i am lost thanks..

[YBinUtah]

about transmission: Have you scanned your car? I had same problem which was transmission malfunctioning. I had to change transmission. Check transmission oil first, and if it doesn't have enough oil, then the problem is transmission.